9. 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
-
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?
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
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
