8. The Periodic Table Flashcards
How are elements arranged on the periodic table?
Elements are arranged on the Periodic Table in order of increasing atomic number, where each element has one proton more than the element preceding it
How is the periodic table arranged?
The table is arranged in vertical columns called Groups numbered 1 – 8 and in rows called Periods
Period definition
these are the horizontal rows that show the number of shells of electrons an atom has
group definition
these are the vertical columns that show how many outer electrons each atom has
Are there patterns and trends on the periodic table? Why/
Because there are patterns in the way the elements are arranged on the Periodic table, there are also patterns and trends in the chemical behaviour of the elements
Where can trends on the periodic table be found?
There are trends in properties down Groups and across a Period
What can you use the trends and patterns on the periodic table to do?
In this way the Periodic table can be used to predict how a particular element will behave
What happens to the metallic character across the periodic table?
The metallic character of the elements decreases as you move across a Period on the Periodic table, from left to right
What happens to the metallic character going down a group?
it increases as you move down a Group
Why does metallic character decrease from left to right?
This trend occurs due to atoms more readily accepting electrons to fill their valence shells rather than losing them to have the below, already full, electron shell as their outer shell
What lies between the metals and non-metals on the periodic table?
Between the metals and the nonmetals lie the elements which display some properties of both
These elements are referred to as metalloids or semi-metals
What is the difference in electron arrangement for metals and non-metals?
M - 1-3 (more in periods 5 & 6) outer shell electrons
N - 4-7 electrons in the outer shell
What is the difference in bonding for metals and non-metals?
M - metallic due to loss of outer shell electrons
N - covalent by sharing outer shell electrons
What is the difference in electrical conductivity for metals and non-metals?
M - good conductors of electricity
N - poor conductors of electricity
What is the difference in type of oxide for metals and non-metals?
M - basic (few are amphoteric)
N - acidic (some are neutral)
What is the difference in reactions with acid for metals and non-metals?
M - many react with acids
N - do not react with acids
What is the difference in physical characteristics for metals and non-metals?
M - malleable can be bent and shaped, high mp and bp
N - flaky, brittle, low mp and bp
Electronic configuration definition
The electronic configuration is the arrangement of electrons into shells for an atom (e.g: the electronic configuration of carbon is 2, 4)
Is there a link between an element’s electronic configuration and its position on the periodic table, if so why?
There is a link between the electronic configuration of the elements and their position on the Periodic table
The number of notations in the electronic configuration will show the number of shells of electrons the atom has, showing the Period
The last notation shows the number of outer electrons the atom has, showing the Group number
What do elements in the same group have in common?
Elements in the same Group in the Periodic table have similar chemical properties
What electrons react during a reaction?
When atoms collide and react, it is the outermost electrons that interact
Why do elements in the same group have similar chemical properties?
The similarity in their chemical properties stems from having the same number of electrons in their outer shell
What are group I metals called and why?
The Group I metals are also called the alkali metals as they form alkaline solutions with high pH values when reacted with water
What are the group 1 metals?
Group 1 metals are lithium, sodium, potassium, rubidium, caesium and francium
What do all group 1 metals have in common?
They all contain just one electron in their outer shell
What are the properties of group 1 metals?
The Group I metals:
Are soft and easy to cut, getting softer and denser as you move down the Group (sodium and potassium do not follow the trend in density)
Have shiny silvery surfaces when freshly cut
Conduct heat and electricity
They all have low melting points and low densities and the melting point decreases as you move down the Group
What chemical properties do all group 1 metals have in common?
They react readily with oxygen and water vapour in air so they are usually kept under oil to stop them from reacting
Group 1 metals will react similarly with water, reacting vigorously to produce an alkaline metal hydroxide solution and hydrogen gas
Describe the reaction of lithium with water
reaction slower than with sodium
- bubbles of hydrogen gas
Describe the reaction of sodium with water
bubbles of hydrogen gas
melts into a shiny ball that dashes around the surface
floats on water because it is less dense
melts because sodium has a low melting point and a lot of heat is made in the reaction
hydrogen is produced which causes the ball of sodium to move around the surface of the water
white trail of sodium hydroxide produced which dissolves in the water producing a highly alkaline solution
Describe the reaction of potassium with water
reacts more violently than sodium
bubbles of gas
melts into a shiny bass that dashes around the surface
enough heat produced so hydrogen burns with a lilac coloured flame
What happens to the reactivity of the elements going down group 1?
The reactivity of the Group 1 metals increases as you go down the group
What do group 1 metals lose when they react?
Each outer shell contains only one electron so when they react, they lose the outer electron which empties the outermost shell
The next shell down automatically becomes the outermost shell and is already full, hence the atom obtains an electronic configuration which has a full outer shell of electrons
Why does reactivity increase going down group 1?
As you go down Group 1, the number of shells of electrons increases by 1 (Period number increases down the Periodic table)
This means that the outer electron is further away from the nucleus so there are weaker electrostatic forces of attraction
This requires less energy to overcome the electrostatic forces of attraction between the negatively charged electron and the positively charged nucleus
This allows the electron to be lost easily, making it more reactive as you go down the Group
Why is it difficult to predict francium’s reaction with water?
Francium is rare and radioactive so is difficult to confirm predictions
What is rubidium’s predicted reaction with water?
explodes with sparks
- rubidium hydroxide produced
What is caesium’s predicted reaction with water?
violent explosion due to rapid production of heat and hydrogen
caesium hydroxide produced
What is francium’s predicted reaction with water?
too reactive to predict
What are the halogens?
These are the Group 7 non-metals that are poisonous and include fluorine, chlorine, bromine, iodine and astatine
What is special about the halogens?
Halogens are diatomic, meaning they form molecules of two atoms
How many electrons do the halogens have in their outer shell?
All halogens have seven electrons in their outer shell
What type of ions do they form and why?
They form halide ions by gaining one more electron to complete their outer shells
What colour is:
- fluorine
- chlorine
- bromine
- iodine
at room temperature
yellow
pale-green
red-brown (readily evaporates to form a brown gas)
black (sublimes to form a purple gas)
What state is:
- fluorine
- chlorine
- bromine
- iodine
at room temperature
gas
gas
liquid
solid
What colour in solution is:
fluorine
chlorine
bromine
iodine
pale yellow
green-blue
orange
dark brown
What happens to the melting boiling points and densities of the halogens going down the group?
The density and melting and boiling points of the halogens INCREASE as you go down the Group
How does the state of the halogens change going down the group?
At room temperature (20 °C), the physical state of the halogens changes as you go down the Group
Chlorine is a gas, bromine is a liquid and iodine is a solid
How does the colour of the halogens change going down the group?
The halogens become darker as you go down the group
Chlorine is pale green, bromine is red-brown and iodine is black
How does the reactivity of the halogens change going down the group?
Reactivity of Group 7 non-metals decreases as you go up the Group
Why does the reactivity decrease as you go down the group?
A
As you go up Group 7, the number of shells of electrons decreases (Period number decreases moving up the Periodic Table)
This means that the outer electrons are closer to the nucleus so there are stronger electrostatic forces of attraction that attract the extra electron needed
This allows an electron to be attracted more readily, so the higher up the element is in Group 7 then the more reactive it is
When does a halogen displacement reaction occur?
A halogen displacement reaction occurs when a more reactive halogen displaces a less reactive halogen from an aqueous solution of its halide
In a reaction of potassium bromide and chlorine, what will be the products?
If you add chlorine solution to colourless potassium bromide solution, the solution becomes orange as bromine is formed
Chlorine is above bromine in Group 7 so is more reactive
Chlorine will therefore displace bromine from an aqueous solution of metal bromide
Potassium Bromide + Chlorine → Potassium Chloride + Bromine
What are 4 properties of the transition elements?
They are very hard and strong metals and are good conductors of heat and electricity
They have very high melting points and are highly dense
metals
The transition metals form coloured compounds and often have more than one oxidation state
Transition metals are often used as catalysts
Do transition elements have more than one oxidation state? Why?
YES
The transition elements have more than one oxidation state, as they can lose a different number of electrons, depending on the chemical environment they are in
Will Compounds containing transition elements in different oxidation states have different properties?
Yes
Compounds containing transition elements in different oxidation states will have different properties and colours
Why are transition elements used as catalysts?
The transition elements are used extensively as catalysts due to their ability to interchange between a range of oxidation states
This allows them to form complexes with reagents which can easily donate and accept electrons from other chemical species within a reaction system
How are transition elements used?
They are used in medicine and surgical applications such as limb and joint replacement (titanium is often used for this as it can bond with bones due to its high biocompatibility)
They are also used to form coloured compounds in dyes and paints, stained glass jewellery
What are the noble gases?
The Noble gases are in Group VIII (or Group O)
What are 4 properties of the noble gases?
Have very low melting and boiling points
They are all monatomic, colourless gases
The Group 0 elements all have full outer shells
This electronic configuration is extremely stable so these elements are unreactive and are inert
What is helium used for? Why?
Helium is used for filling balloons and weather balloons as it is less dense than air and does not burn
What is neon used for? Why?
Neon, argon and xenon are used in advertising signs
What is argon used for? Why?
Argon is used to provide an inert atmosphere for welding
Argon is also used to fill electric light bulbs as it is inert
What is the purpose of the periodic table?
Its a way of classifying the elements
In what order is the periodic table arranged?
Shows elements in order of their proton number
What is PERIODICITY?
When elements with similar properties appear at regular intervals
What are the columns called
groups
What are the rows called?
Periods
What does the group number correlate to?
Same as the number of outer-shell electrons
What are the outer-shell electrons called?
valency electrons
Why are valency electrons important?
They dictate how an element behaves
Why do elements in the same group have similar reactions?
have the same number of valency electrons
Do group 0/8 elements react?
Why?
NO
have a very stable electron arrangement
are unreactive
full outer electron shell
What does the period of an element tell you?
Tells you the number of electron shells the atom has
What is the nucleon number?
Total number of particles in the nucleus
protons + neutrons
Group 1 different name
alkali metals
Group 2 different name
alkaline earth metals
Group 7 different name
halogens
Group 8/0 different name
noble gases
What percentage of the elements are metals?
over 80%
Why is hydrogen alone in the periodic table?
Properties
has 1 valency electron
forms a positive ion (H+)
similar to group 1 metals but it is A GAS
reacts like a non-metal
Revise the properties of metals and non-metals
yes
What are artificial elements and why can they not be found in nature?
elements made in a lab
- are radioactive and their atoms break down very quickly
list the group 1 metals
lithium, sodium, potassium, rubidium, caesium, francium
list the physical properties of group 1 metals
good conductors of heat and electricity
softer than most other metals (can cut with a knife)
low density (float on water) ctom
low melting and boiling points ctom
ctom - compared to other metals
trends in softness g1
softness increases going down the group
trends in density g/cm3 g1
density increases going down the group
trends in melting point g1
mp decreases going down the group
trends in reactivity g1
reactivity increases going down the group
lithium reaction with water
floats and fizzes
sodium reaction with water
shoots across the water
potassium reaction with water
melts with the heat of the reaction, hydrogen catches fire producing lilac flame
Overall description of group 1 metals with water
Alkali metals react vigorously with water.
Hydrogen bubbles off, leaving solutions of their hydroxides, which are alkalis.
chemical equation of lithium/sodium with water
2Na + 2H20 –> 2NaOH + H2
2Li + 2H2O –> 2LiOH + H2
etc
chemical equation of lithium/sodium with water
2Na + 2H20 –> 2NaOH + H2
2Li + 2H2O –> 2LiOH + H2
etc
Overall description of group 1 metals with chlorine
If you heat the 3 metals and plunge them into gas jars of chlorine, they burst into flames.
Burn brightly forming chlorides
Overall equation for group 1 metals with chlorine
2Li + Cl2 –> 2LiCl
2Na + Cl2 –> 2NaCl
Overall description of group 1 metals with oxygen
Burst into flames when heated and plunged into gas jars of oxygen
Form oxides
Are group 1 oxides acidic or alkaline
alkaline
- dissolve in water to form alkaline solutions
Why are group 1 metals the most reactive?
have only 1 valency electron
strong drive to react with other elements and compounds, in order to give up this electron
lose electron to form ions
What compounds do g1 metals make?
IONIC compounds
What charge do all the ions in group 1 have?
+1
What colour are group 1 compounds?
What colour do they form when they dissolve?
white solids
colourless solutions when dissolved in water
Why does reactivity increase going down group 1?
in reactions, group 1 atoms lose their outer electron to gain a stable outer shell
the more shells there are, the further the valence electron is from the positive nucleus - easier to lose
easier the valence electron is to lose, more reactive a metal will be
List group 7 elements
fluorine, chlorine, bromine, iodine
3 properties of halogens
form coloured gases
are poisonous
for diatomic molecules (containing 2 atoms)
What colour is … in gaseous form?
fluorine
chlorine
bromine
iodine
pale yellow
green
red
purple
Trend for colour for halogens
colour gets deeper going down the group
Trend for denisty for halogens
density increases going down the group
Trend for bp for halogens
the boiling point increases going down the group
Trend for reactivty for halogens
reactivity DECREASES going down the group
Overall reaction for halogens with metals
React to form halides
Fluorine reaction with iron wool
Iron wool bursts into flames
- no heating required
chlorine reaction with iron wool
hot iron wool glows brightly
bromine reaction with iron wool
hot iron wool glows, less brightly
iodine reaction with iron wool
hot iron wool shows a faint red glow
Why are the halogens so reactive?
need just one more electron to reach a stable outer shell
strong drive to react with other elements or compounds to gain this electron
they accept electrons (w/metals) / share them (w/non-metals)
Why does reactivity decreases going down group 7?
halogen atoms react to gain or share an electron
positive nucleus of the atom attracts the electron
more outer shells there are, further, the outer shell is from the nucleus
attracting an electron becomes difficult
Overall rule for halogen reactions with halides
A halogen will displace a less reactive halogen from a solution of its halids
Cl2 + 2KBr –> 2KCl + Br2
Group 8/0 list elements
helium, neon, argon, krypton, xenon
properties of noble gases (5)
non-metals
colourless gasses
occur naturally in air
MONOATOMIC - exist as single atoms
unreactive
Why are noble gases monoatomic and unreactive?
Their elements already have a stable outer shell
Where do we get the noble gases from?
Fractional distillation of liquid air
- helium is obtained from natural gas (it’s an impurity)
trend in atoms for group 8
atoms increase in size and mass going down the group
trend in density for group 8
density of gas increases going down the group
trend in density for group 8
density of gas increases going down the group
trend in boiling point for group 8
the boiling points increase going down the group
What does the increase in boiling points show?
A sign of increasing attraction between atoms
- harder to separate them to form a gas
What happens when a current is passed through noble gases at a low pressure?
They glow
Uses for helium
used to fill balloons and airships
- won’t catch fire and lighter than air
Uses for argon
used to provide an inert atmosphere
as a filler in tungsten light bulbs
to protect metals that are being welded
Uses for neon
used in advertising signs
glows red
colour can be changed by mixing with other gases
uses for krypton
used in lasers
e. g eye surgery / car headlamps
Uses for xenon
gives a bright light with a blue tinge
used in lighthouse lamps
lights for hospital operating rooms
car headlamps
What are the transition elements?
Block of 30 elements in the middle of the periodic table.
What are the transition elements?
Block of 30 elements in the middle of the periodic table.
Physical properties of transition metals (5)
hard, tough and strong
high melting points (mercury is an exception)
malleable, ductile
good conductors of heat and electricity
high density
which metal is the best conductor?
silver
and then copper
Chemical properties of transition metals (6)
much less reactive than group 1 metals
show no clear trend in reactivity
most transition elements form coloured compounds
most can form ions with different charges
form more than one compound with another element
most can form complex ions
In general, do transition elements corrode easily?
No
- iron is an exception - it rusts easily
What is the name for elements that form many ions with different charges?
They have a VARIABLE VALENCY
How do you make salt of a transition element?
react their oxide/hydroxide with acids
their oxides are basic and react with acids to form salts
What do the roman numerals in brackets tell you? e.g (II)
how many electrons the metal atom has lost
- OXIDATION STATE
Uses of the transition elements? (4)
used in structures such as bridges, buildings, cars.
used in making alloys
used as conductors of heat and electricity e.g copper for electric wiring
most act as catalysts e.g iron is used in making ammonia
What transition element is most commonly used in making structures?
Iron is most widely used usually in the form of alloys called steels
what is an alloy?
Small amounts of other substances are mixed with a metal to improve its properties
What is used to create stainless steel?
chromium and nickel
Trends across the periodic table (left to right)
2
go from metals to non-metals
- mp and bp rise to the middle of the period (IV), then fall to very low values on the right
What type of conductors are metalloids known as?
Semi-conductors
What does valency mean?
The valency of an element is the number of electrons its atoms lose, gain or share, to form a compound
What does the valency match?
number of valency electrons (up to group IV)
- matches the charge on the ion, where an element forms ions
Rules for electron transfer for metals and non-metals
metals - lose their outer electrons
non-metals - gain or share electrons
trends in reactivity for non/metals
reactivity
decreases across metals
reactivity increases for non-metals
across the periods
Why does reactivity decrease for metals across the period?
The more electrons a metal atom needs to lose, the more difficult it is (must have enough energy to overcome the pull of the nucleus)
Why does reactivity increase for non-metals across the period?
(except group 0)
The fewer electrons a non-metal needs to gain, the easier it is to attract them
Alkali Metals
> Group 1
Very reactive, have to be stored in oil.
Low density
Very soft, can be cut with a knife
Silvery, shiny until they react with the oxygen in the air.
Low melting/boiling points.
Reaction with water produces a metal hydroxide.
All soluble in water. Produce a colourless solution with an alkaline pH.
More reactive down the group.
The Transition Elements
> Good conductors
Hard and Strong
High Density
High Melting and Boiling Points (except Mercury)
Not v. reactive.
Often used as catalysts
Charge often given in the name (Iron (II))
The Halogens
> Group 7
Poisonous non-metals
Low melting and boiling points
Poor conductors
Reactivity decreases down the group
More reactive Halogens displace less reactive ones.
What is harder for large atoms?
gaining extra electrons
What is easier for large atoms?
losing electrons
Why do the Alkali Metals get more reactive going down?
Because the atoms get bigger, and the outer shell is further away from the nucleus.
This means the electrostatic attraction is weaker.
The other, inner shells, also shield the outer shell from the electrostatic attraction.
This means that it is easier for the outer electron to be removed.
Why do the Halogens get less reactive going down?
Because of the shielding of the inner shells and lack of electrostatic attraction to the outer shell, it is harder for the bigger atoms to attract electrons.
What is the periodic table a method of?
method of classifying elements and its use to predict properties of elements
What is the change from metallic to non-metallic
character across a period?
Metallic character decreases
How is the number of occupied shells determined?
determined by the period number
How is the number of valence electrons determined?
determined by the group number
What are the physical properties of Group I Metals? (3)
Soft
Grey, shiny when cut quickly tarnishes
Relatively low mp and bp + density
What is the chemical trend in Group I Metals?
gets more reactive as you go down the group
What are the physical trends in Group I Metals? (2)
gets softer and lower mp and bp as you go down the group
density of metals increase as you go down group
What is produced when alkali metals react with water?
alkali metal + water => metal hydroxide + hydrogen
What are the physical properties of Halogens? (4)
poisonous/strong smell, coloured, poor conductors, non metals
What are the physical trends in Halogens? (2)
gets a darker colour and higher mp and bp as you go down the group
What is the chemical trend in Halogens? (2)
gets less reactive as you go down the group
What is halide displacement?
when a more reactive halogen displaces a less reactive halogen from an ionic compound.
What are the properties of transition metals? (5)
Hard and strong
High density
High mp and bp
Coloured compounds
Have more than once valency
What is monoatomic?
exist as single atom
What is diatomic?
exist as a two atom molecule
F₂ appearance
pale yellow gas
Cl₂ appearance
pale green gas
Br₂ appearance
red-brown liquid
I₂ appearance
grey solid (with purple vapour)
I₂ appearance
grey solid (with purple vapour)
What are noble gas properties?
unreactive
monoatomic gases
Noble gases are used to provide an __ atmosphere
inert
use of argon + property
the gas inside light bulbs
inert so doesn’t react at high temperatures
use of helium + property
the gas inside balloons
low density so floats in air
What is the name of the first group?
Alkali Metals
What are the four characteristics of group 1?
more reactive as they go down
Softer as they go down
density increases as they go down
melting point increases as they go down
What is the equation for any metal with water?
2X +2H2O => 2XOH + H2
What is the name of group 2?
Alkali Earth Metals
Name 6 properties of transition metals
they have high melting points
hard tough and strong
react slowly w oxygen and water
iron is used for building/ copper is used for electrical cables
transition metals form colored compounds
some are catalysts
Give 4 properties of metals?
Malleable
ductile
Conductors of heat
Conductors of electricity
Give 2 things that metals form
Positive ions
Basic oxides
Give 4 properties of non- metals
brittle
non- ductile
insulators of heat
insulators of electricity
Give 2 things that non- metals form.
Negative ions
Acidic oxides
Name all the elements of group 7 and their state
F GAS
Cl GAS
BR LIQUID
I SOLID
At SOLID
Show the trends of Halogens
Get darker in color as they go down
Become less reactive as they go down
Melting/Boiling point increases as they go down
Show the trends of noble gases
Boiling point increases as they go down
The atoms increase in size and mass as they go down
density of mass increases as they go down
What are the uses of helium and why?
Fill balloons and airships
Because it is lighter than air and does not burn
What are the uses of neon and why?
advertising signs
Glow when a current is passed through them
What are the uses of argon and why?
Filler in tungsten bulbs
Protect melted that are being welded
unreactive
What are the uses of Krypton and why?
Used in lasers and car head lamps
Unreactive/inert
What are the uses of xenon and why?
Used in light house lamps, lights in hospital operating room
Glow when a current is passed through them
What is the bonding between Non- metal and non- metal?
covalent
Metal and metal?
Metallic
Non metal and metal?
Ionic
What are the two physical properties of flerovium?
High melting point
Malleable
Give 2 observations when potassium is added to cold water
Moves around
Flame
Write a chemical equation for the reaction of calcium with cold water.
Ca+2H20 -> Ca(OH)2 + H2
Describe a test for hydrogen
Test: Lit splint placed on mouth of apparatus
Result: You hear a pop
One physical property that is similar for both cobalt and potassium
They are both conductors of electricity
State one physical property that is different for cobalt and potassium
They have different melting points
What is the periodic table?
an arrangement of elements in periods and groups and in order of increasing proton number/ atomic number
Describe the change from metallic to
non-metallic character across a period
as we move from left to right across a period in the periodic table, the metallic character of the elements decreases while the non-metallic character increases. This transition is due to the increasing nuclear charge, which results in a stronger attraction between the nucleus and the valence electrons, making it more difficult for the electrons to be removed from the atom and increasing the tendency to form anions.
What is the metallic character related to?
Metallic character is related to the tendency of an element to lose electrons and form cations, while non-metallic character is related to the tendency of an element to gain electrons and form anions.
Describe the relationship between group number
and the charge of the ions formed from elements
in that group
A
The charge of ions formed from elements in a particular group of the periodic table is related to the number of valence electrons in the outermost shell of the atoms.
In Group 1 of the periodic table, which includes elements like lithium, sodium, and potassium, the atoms have one valence electron. When they react with other elements, they tend to lose this one valence electron to form cations with a charge of +1.
In Group 2 of the periodic table, which includes elements like beryllium, magnesium, and calcium, the atoms have two valence electrons. When they react with other elements, they tend to lose these two valence electrons to form cations with a charge of +2.
In Group 13, which includes elements like boron, aluminum, and gallium, the atoms have three valence electrons. When they react with other elements, they can lose all three valence electrons to form cations with a charge of +3.
In Group 16, which includes elements like oxygen, sulfur, and selenium, the atoms have six valence electrons. When they react with other elements, they tend to gain two electrons to form anions with a charge of -2.
In Group 17, which includes elements like fluorine, chlorine, and bromine, the atoms have seven valence electrons. When they react with other elements, they tend to gain one electron to form anions with a charge of -1.
In general, as we move from left to right across a period of the periodic table, the elements have an increasing number of valence electrons, which tends to make them more likely to gain electrons and form anions. As we move down a group, the number of valence electrons tends to remain the same, but the size of the atoms increases, making them more likely to lose electrons and form cations.
Explain similarities in the chemical properties of
elements in the same group of the Periodic Table
in terms of their electronic configuration
The chemical properties of elements in the same group of the periodic table are similar because they have the same number of valence electrons in their outermost shell. The valence electrons are the electrons that are involved in chemical bonding, and they determine the way in which an atom interacts with other atoms to form compounds.
For example, the elements in Group 1 of the periodic table all have one valence electron in their outermost shell. This means that they all have similar chemical properties when they react with other elements. They tend to lose this valence electron to form ions with a charge of +1, and they are very reactive metals that readily form ionic compounds with non-metals such as halogens.
Similarly, the elements in Group 17 of the periodic table all have seven valence electrons in their outermost shell. This means that they all have a strong tendency to gain one electron to form anions with a charge of -1. They are all highly reactive non-metals that readily form ionic compounds with metals such as Group 1 metals.
The elements in other groups of the periodic table also have similar chemical properties based on the number of valence electrons in their outermost shell. For example, the elements in Group 2 all have two valence electrons and tend to lose these electrons to form ions with a charge of +2, while the elements in Group 16 all have six valence electrons and tend to gain two electrons to form ions with a charge of -2.
In general, the number of valence electrons in an atom determines its chemical properties, and elements with the same number of valence electrons in their outermost shell tend to have similar chemical properties.
Explain how the position of an element in
the Periodic Table can be used to predict its
properties
Atomic structure: The position of an element in the periodic table provides information about its atomic structure. The atomic number of the element is the number of protons in the nucleus of the atom. The number of protons determines the element’s identity and its position in the periodic table. The number of electrons in the outermost shell (valence electrons) determines the element’s chemical properties.
Periods: The elements in the same period have the same number of electron shells. The properties of the elements change across a period from metallic to non-metallic character. Elements in the same period have similar atomic radii and ionization energies.
Groups: The elements in the same group have the same number of valence electrons. Elements in the same group have similar chemical properties, such as reactivity, ionization energy, and electronegativity. The elements in the same group tend to have the same valence electron configuration, and this determines their chemical behavior.
Metals and Non-Metals: Elements in the left-hand side of the periodic table are typically metals, and elements on the right-hand side are typically non-metals. This trend holds true in general, with some exceptions in the transition metals.
Chemical Reactivity: The position of an element in the periodic table can predict its chemical reactivity. The reactivity of elements increases as you move down the periodic table within a group, and decreases as you move across a period from left to right. This is due to changes in the atomic radius, ionization energy, and electronegativity.
In summary, the position of an element in the periodic table can be used to predict its atomic structure, chemical properties, and physical properties. This information can be used to understand how an element will react with other elements and to predict the properties of new compounds.
Describe the Group I alkali metals, lithium,
sodium and potassium
relatively soft metals
with general trends down the group
the Group I alkali metals, lithium, sodium and potassium, exhibit general trends down the group, such as decreasing melting point, increasing density and increasing reactivity. These properties can be explained by the increasing atomic size and the corresponding changes in the electronic configuration of the elements in the group.
What is the general trend down the group of Group 1 alkali metals
(a) Decreasing melting point:
As we move down the group, the melting points of the alkali metals decrease. This is because the metallic bonds between the atoms become weaker, due to the increasing distance between the positively charged atomic nuclei and the negatively charged delocalized electrons. This means that less energy is required to break these bonds and the melting points decrease.
(b) Increasing density:
As we move down the group, the density of the alkali metals increases. This is because the size of the atoms increases as we move down the group, and this causes an increase in the number of atoms per unit volume, resulting in an increase in the density.
(c) Increasing reactivity:
As we move down the group, the alkali metals become more reactive. This is because the outermost electron of each atom is further away from the nucleus, which makes it easier to remove that electron, resulting in a lower ionization energy. Therefore, the alkali metals are more likely to lose this outermost electron and form positively charged ions, which makes them highly reactive.
Predict the properties of other elements in
Group I, given information about the elements
Based on the properties of these elements, we can predict the properties of other elements in the group:
Increasing atomic size: As we move down the group, the atomic size of the elements increases. Therefore, we can predict that the atomic size of the other elements in Group I will also increase down the group.
Decreasing ionization energy: The ionization energy decreases down the group as the outermost electron becomes further from the positively charged nucleus. Therefore, we can predict that the ionization energy of the other elements in Group I will also decrease down the group.
Increasing reactivity: The alkali metals are highly reactive due to their low ionization energy and tendency to lose their outermost electron to form a +1 ion. Therefore, we can predict that the other elements in Group I will also be highly reactive.
Increasing melting and boiling points: The melting and boiling points of the elements in Group I increase down the group due to the increasing strength of metallic bonds. Therefore, we can predict that the melting and boiling points of the other elements in Group I will also increase down the group.
Increasing density: The density of the elements in Group I increases down the group due to the increasing atomic mass and number of atoms per unit volume. Therefore, we can predict that the density of the other elements in Group I will also increase down the group.
In summary, based on the properties of the known elements in Group I, we can predict that other elements in the group will also exhibit similar trends, such as increasing atomic size, decreasing ionization energy, increasing reactivity, increasing melting and boiling points, and increasing density down the group.
Describe the Group VII halogens, chlorine,
bromine and iodine
diatomic non-metals with general trends down the group
Describe the Group VII halogens trends going down the group
(a) Increasing density: As we move down the group, the atomic size of the halogens increases due to the addition of more electron shells. This causes an increase in forces between the atoms, leading to an increase in the density of the halogens. Therefore, the density of chlorine, bromine, and iodine increases down the group.
(b) Decreasing reactivity: As we move down the group, the reactivity of the halogens decreases. This is because the outermost electron is increasingly farther away from the positively charged nucleus, which reduces the attraction between the electron and the nucleus. This leads to a decrease in the ability of the halogens to attract electrons from other atoms or molecules. Therefore, the reactivity of chlorine, bromine, and iodine decreases down the group.
Chlorine is the most reactive halogen, while iodine is the least reactive. Chlorine readily reacts with most metals to form ionic halides, while bromine reacts with fewer metals and iodine reacts with even fewer metals. Iodine is relatively unreactive and is typically only involved in reactions with more reactive elements or compounds.
In summary, the halogens chlorine, bromine, and iodine are diatomic non-metals with general trends down the group of increasing density and decreasing reactivity.
State the appearance of chlorine at r.t.p
State the appearance of chlorine at r.t.p
State the appearance of bromine at r.t.p
a red-brown liquid
State the appearance of iodine at r.t.p
a grey-black solid
Describe and explain the displacement reactions
of halogens with other halide ions
The displacement reactions of halogens with other halide ions occur because halogens are more reactive than other halide ions. In a displacement reaction, a more reactive halogen will displace a less reactive halogen from its compound. For example, when chlorine gas is bubbled through a solution of potassium bromide, the chlorine will displace the bromine from the potassium bromide, and potassium chloride and bromine will be formed.
The reactivity of halogens decreases down the group, so a halogen higher up the group can displace a halogen lower down the group from a compound. For example, chlorine can displace both bromine and iodine from their compounds.
The displacement reactions of halogens with other halide ions can be explained in terms of the relative strength of the covalent bond between the halogen and the halide ion. A more reactive halogen has a stronger bond with the halide ion and can more easily displace a less reactive halogen with a weaker bond.
These displacement reactions are important in the production of certain chemicals, such as chlorine and iodine, and can also be used to test for the presence of halide ions in a sample. For example, adding chlorine water to a solution of an unknown halide salt will produce a precipitate of the halide ion that can be identified by its colour. Chlorine water will produce a white precipitate of silver chloride with a solution containing silver ions, a cream precipitate of silver bromide with a solution containing bromide ions, and a yellow precipitate of silver iodide with a solution containing iodide ions.
Describe and explain the displacement reactions
of halogens with other halide ions
The displacement reactions of halogens with other halide ions occur because halogens are more reactive than other halide ions. In a displacement reaction, a more reactive halogen will displace a less reactive halogen from its compound. For example, when chlorine gas is bubbled through a solution of potassium bromide, the chlorine will displace the bromine from the potassium bromide, and potassium chloride and bromine will be formed.
The reactivity of halogens decreases down the group, so a halogen higher up the group can displace a halogen lower down the group from a compound. For example, chlorine can displace both bromine and iodine from their compounds.
The displacement reactions of halogens with other halide ions can be explained in terms of the relative strength of the covalent bond between the halogen and the halide ion. A more reactive halogen has a stronger bond with the halide ion and can more easily displace a less reactive halogen with a weaker bond.
These displacement reactions are important in the production of certain chemicals, such as chlorine and iodine, and can also be used to test for the presence of halide ions in a sample. For example, adding chlorine water to a solution of an unknown halide salt will produce a precipitate of the halide ion that can be identified by its colour. Chlorine water will produce a white precipitate of silver chloride with a solution containing silver ions, a cream precipitate of silver bromide with a solution containing bromide ions, and a yellow precipitate of silver iodide with a solution containing iodide ions.
Predict the properties of other elements in
Group VII, given information about the elements
As we move down Group VII:
The size of the atoms increases, due to the addition of more electron shells.
The boiling and melting points increase, due to the increased strength of the van der Waals forces between molecules.
The density of the elements increases, due to the increased size of the atoms and the increased strength of the van der Waals forces.
The reactivity decreases, due to the increasing distance between the outer electrons and the nucleus, and the increasing shielding of the inner electrons.
Based on these trends, we can predict that other elements in Group VII would have similar properties. For example, an element below iodine would likely have a higher melting and boiling point, higher density, and lower reactivity than iodine. However, as we move down the group, the trends become less pronounced, and the properties of the elements become more diverse. Additionally, astatine, the last element in the group, is radioactive and has a very short half-life, so it is difficult to study its properties.
Describe the transition elements
have high densities
have high melting points
form coloured compounds
often act as catalysts as elements and in
compounds
Describe transition elements as having ions with
variable oxidation numbers, including iron(II) and
iron(III)
iron, which is a transition element, can form ions with an oxidation state of +2 or +3. These ions are commonly known as iron(II) and iron(III) ions, respectively.
Iron(II) ion, also known as ferrous ion, has two fewer electrons than the neutral iron atom, and it has a +2 charge. This ion is formed when an iron atom loses two electrons. Iron(II) ion is a pale green color and is easily oxidized to the +3 oxidation state.
Iron(III) ion, also known as ferric ion, has three fewer electrons than the neutral iron atom, and it has a +3 charge. This ion is formed when an iron atom loses three electrons. Iron(III) ion is a reddish-brown color and is not easily reduced to the +2 oxidation state.
The ability of transition elements to form ions with variable oxidation states is due to the presence of partially filled d orbitals in their electron configuration. The d orbitals are involved in chemical reactions and can be easily involved in the transfer of electrons, allowing for the formation of ions with different charges.
In summary, transition elements have ions with variable oxidation numbers due to the presence of partially filled d orbitals in their electron configuration. Iron, a transition element, can form ions with an oxidation state of +2 or +3, commonly known as iron(II) and iron(III) ions, respectively.
Describe the Group VIII noble gases
unreactive, monatomic gases due to their full outer shells
How are elements arranged in the periodic table?
Elements are arranged in order of increasing proton number or atomic number.
What are horizontal rows called?
Horizontal rows are called periods.
What are vertical columns called?
Vertical columns are called groups.
Why is there a progressive change in the properties of the elements on going across a period?
The number of electrons possessed by an element influences its chemical properties and as each element within a period has one more valency electron than the proceeding element, there is a progressive change in the properties of the elements on going across a period.
Period 1 consists of only two elements because the 1st electron shell can only hold 2 electrons.
Name the two Period 1 elements.
Hydrogen - can form both positive and negative ions.
Helium - proton number of 2 - simplest noble gas as its outermost electron shell is full.
The second period consists of eight elements because the second element shell can only hold 8 electrons.
Name the eight elements.
Lithium.
Beryllium.
Boron.
Carbon.
Nitrogen.
Oxygen.
Fluorine.
Neon.
What is lithium (second period element)?
Has one electron in its outermost shell and is a soft silvery reactive metal.
What is beryllium (second-period element)?
Has atoms with two electrons in their outermost shell and is a silvery metal but is less reactive than lithium.
What is boron (second-period element)?
Has three electrons in its outermost shell and is a black solid with few metallic properties and cannot conduct electricity.
What is carbon (second-period element)?
Has four electrons in its outermost shell and is non metallic but can conduct electricity and is unreactive.
What is nitrogen (second-period element)?
Has five electrons in its outermost shell and is a colorless gas, is unreactive and is a non-metal.
What is oxygen (second-period element)?
Has six electrons in its outermost shell, colorless gas and is more reactive than Nitrogen.
What is fluorine (second-period element)?
Has seven electrons in its outermost shell, is a pale yellow gas, is very reactive and very electronegative (ability to attract electrons).
What is neon (second-period element)?
Has eight electrons in its outermost shell, is an inert/ noble gas.
The third period also consists of eight elements which increase in non-metallic properties across the period from left to right.
Name the eight elements.
Sodium.
Magnesium.
Aluminum.
Silicon.
Phosphorus.
Sulfur.
Chlorine
Argon.
Give the following information about Sodium:
Appearance.
Proton Number.
Electronic Structure.
Classification.
Nature of oxide.
Usual valency.
Silver metal
11
2,8,1
Metal
Basic oxide
Ionic
1
Give the following information about Magnesium:
Appearance.
Proton Number.
Electronic Structure.
Classification.
Nature of oxide.
Usual valency.
Silver metal
12
2,8,2
Metal
Basic oxide
Ionic
2
Give the following information about Aluminium:
Appearance.
Proton Number.
Electronic Structure.
Classification.
Nature of oxide.
Usual valency.
Silver metal
13
2,8,3
Metal
Amphoteric oxide
Ionic
3
Give the following information about Silicon:
Appearance.
Proton Number.
Electronic Structure.
Classification.
Nature of oxide.
Usual valency.
Black solid
14
2,8,4
Non-metal
Acidic oxide
Covalent
4
Give the following information about Phosphorus:
Appearance.
Proton Number.
Electronic Structure.
Classification.
Nature of oxide.
Usual valency.
Yellow solid
15
2,8,5
Non-metal
Acidic oxide
Covalent
3
Give the following information about Sulfur:
Appearance.
Proton Number.
Electronic Structure.
Classification.
Nature of oxide.
Usual valency.
Yellow solid
16
2,8,6
Non-metal
Acidic oxide
Covalent
2
Give the following information about Chlorine:
Appearance.
Proton Number.
Electronic Structure.
Classification.
Nature of oxide.
Usual valency.
Green gas
17
2,8,7
Non-metal
Acidic oxide
Covalent
1
Give the following information about Argon:
Appearance.
Proton Number.
Electronic Structure.
Usual valency.
Colorless gas
18
2,8,8
0
The fourth period is a long period and contains 18 elements - 10 of which are produced when the third shell containing eight electrons increases from 8 to 18. They have similar properties because of their similar electronic configurations.
They are all metals but differ from the outer block metals in a number of important ways:
They have relatively high melting points and high densities.
They form colored compounds.
They have more than one valency/ oxidation state.
Both metals and compounds can act as catalysts.
They are less reactive than metals in other groups.
Name a physical property of noble gases.
The density of the noble gases increases down the group with helium and neon being lighter than air and the others not.
What is the group eight element called helium used for?
Used in weather ballons and airships because it is lighter than air.
A mixture of helium and oxgen is used by deep sea divers.
What is the group eight element called argon used for?
Argon is used as an inert atmosphere to extract titanium to stop the metal oxidizing as it is extracted and during wielding.
We also use argon in electric light bulbs containing tungsten filament to prevent filament burning.
What is the group eight element called neon used for?
Neon is used in advertisement signs because it glows when a high voltage is passed through it.
What is the group eight element called krypton used for?
Krypton is used in lasers for eye surgery and in bulbs for car headlamps.
What is the group eight element called xenon used for?
Xenon is used in lamps where a high bright light is required and also used in lasers.
What are group 7 and group 1 elements called?
Group 7 = Halogens
Group 1 = Alkali metals
Reactivity trend in group 7 and group 1?
More reactive as you go down group 1
- More reactive as you go up in group 7
