C1- Atomic Structure and the Periodic Table Flashcards
Can you see atoms with a microscope?
No they are too small
What do atoms contain?
Protons ,neutrons and electrons
Where is the nucleus in the atom?
Middle
Where are the protons and neutrons within the atom?
The nucleus
What charge does the nucleus have?
Positive
How much of the mass of the atom is concentrated in the nucleus?
Almost all of it
What do electrons move around the nucleus in?
Electron shells
What charge do electrons have?
Negative
What changes the volume of the electrons orbit?
The size of the atom
How much mass does the electron have?
Virtually none
How many more electrons does an atom have than protons?
None
What charge do atoms have and why?
Neutral ,they have the same number of protons and electrons
In an ion does the number protons equal the number of electrons?
No
What number on each element on the periodic table describes the element?
Atomic number and mass number
What does the atomic number tell you about an atom?
How many protons there are
What does the mass number tell you about an atom?
The total number of protons and neutrons in the atom
How to get the number of neutrons?
Subtract the atomic number from the mass number
What is an element?
A substance made up of atoms that all have the same number of protons in their nucleus
How many different atomic numbers do the atoms have within the elements?
They are all the same
What within the atom nucleus determinants what type of atom it is?
The number of protons
What is a substance called if it only contains atoms with the same number of protons?
Element
How many different elements are there (roughly)?
100
What are isotopes?
The same as elements apart from extra neutrons
Do isotops have the same number of protons as the element?
Yes
Because elements can exists a number of different isotopes what is used instead of mass number?
Relative atomic mass
What is relative atomic mass?
An average mass taking into account the different masses and abundances (amounts) of all the isotopes that make up the element
What is the formula for working out the relative atomic mass of an element
relative atomic mass=sum of(isotope abundance x isotope mass number/sum of abundances of all the isotopes
What do atoms join together to make?
Compounds
What are compounds?
Substances formed from two or more elements, the atoms of each are in fixed proportions throughout the compound and they’re held together by chemical bonds
How do atoms make bonds?
Give away, take or share electrons
Are the nuclei effected by bonds made in atoms?
No
What needs to happen to separate the original element of a compound ?
A chemical reaction
What type of substance is made from a non-metal and metal?
An ion
When forming an ion does the metal loose electrons or loose them?
Loose
What does a compound made from non-metals consist of?
Molecules
What is covalent bonding?
Each atom shares an electron with another atom
Are the properties of a compound normally similar to the original element?
No
How are chemical changes shown?
Using chemical equations
Do symbol equations show the atoms on one side?
No ,both
Do symbol equations need to be balanced?
Yes
Can mixtures be easily separated?
Yes
Are there any chemical bonds between different elements in a mixture?
No
Can elements and compounds be part of a mixture?
Yes
How can u separate mixtures?
Physical methods
Name four examples of physical methods to separate mixtures?
- Filtration
- Crystallisation
- Simple distillation
- Fractional distillation
- Chromatography
Is air a mixture, element or compound?
Mixture
What elements are in the air?
- Nitrogen
- Oxygen
- Carbon dioxide
- Argon
What is in crude oil?
A mixture of different length hydrocarbon molecules
Are the properties of mixture just a mixture of the properties of the separate parts?
Yes
When did John Dalton have theory of the atom?
The start of the 1800s
What was John Dalton’s theory of the atom?
He described atoms as a solid spheres and said that different spheres made up the different elements
What scientist had a theory on the atom in 1897?
J J Thomson
What was JJ Thomson’s theory of the atom?
- Atoms weren’t solid spheres
- He showed the atoms could contain even smaller negatively charged particles-electrons
- he came up with the plum pudding model
What did the plum pudding model show?
The atoms as a ball of positive charge with electrons stuck in it
Who showed that the plum pudding model was wrong?
Ernest Rutherford
When was it shown that the plum pudding model was wrong?
1909
What experiment showed the plum pudding model was incorrect ?
Alpha particle scattering experiment
What was the alpha particle scattering experiment?
Ernest Rutherford and his student Ernest Marsden fired positively charged alpha particles at extremely thin sheet of gold
What were the people conducting the alpha particle scattering experiment expecting to happen based on the plum pudding model?
The particles to go straight through or be slightly deflected at most
What did the particles do in the alpha particle scattering experiment?
- Some deflected backwards ( more than expected)
- Most went straight through
- A small number deflected backwards
What was Ernest’s Rutherford particle model called?
The nuclear model
What is the nuclear model?
There is a tiny positive positively charged nucleus in the centre, where most of the mass is concentrated. A ‘cloud’ of negative electrons surrounds this nucleus- so most of the atom is empty space .
Who realised that Ernest Rutherford’s model was incorrect?
Niels Bohr
Why did the scientist realise that Ernest Rutherford?
If there were a cloud of electrons they would be attracted to the nucleus causing the atom to collapse?
What new thing did Niels Bohr’s model have?
Shells and the electrons orbit the nucleus in fixed shells and aren’t anywhere in-between. Each shell in a fixed distance from the nucleus.
Was Neil Bohr’s model supported by experiment ?
Yes
Who showed there were protons?
Rutherford
How many years after scientists said there was a nucleus in an atom did a scientist come up with the idea that there are neutrally charged particles?
20
Who first said there neutrons?
James Chadwick
What are five electron rules?
-Electrons always occupy shells (sometimes called energy levels)
-The lowest energy levels are always filled first - these are the ones closest to the nucleus
-Only a certain number of electrons are allowed in each cell:
1st shell: 2 2nd shell: 8 3rd shell: 8
-Atoms are much happier when they have full electron shells- like the noble gases
-In most atoms, the outer shell is not full and this makes the atom want to react to fill it
What number in the first 20 elements tells you the number of protons?
Atomic number
How were elements arranged in the 1800s?
By atomic mass
Until recently what were the 2 obvious ways to categorise elements?
- Their physical and chemical properties
- Their relative atomic mass
When did scientists realise that they could arrange elements by atomic number?
After they discovered protons neutrons and electrons. 20th century
What were the issues with early periodic tables?
- They were not complete
- Some elements were placed in the wrong group
What did Dmitri Mendeleev do that was special when creating his periodic table?
He left gaps
In what year did Dmitri Mendeleev create his first periodic table ?
1869
How many elements were in Dmitri Mendeleev original periodic table?
50
How did Dmitri Mendeleev mainly order the elements?
In order of atomic mass
When were isotopes discovered?
20th century
What is the main reason for how elements are laid out?
Increasing atomic (proton) number
Which side of the periodic table are metals on?
left
How are elements with similar properties laid out on the periodic table?
They are in columns
What are the vertical columns called?
Groups
What does the group number tells you?
The number of electrons in the outer shell
What is the exception for the group number telling you what it tells you?
Group 0
How can you predict what the properties of one element knowing the properties of another?
If they are in the same group they have similar properties
What are rows called in the periodic table?
Periods
What do the periods tell you in the periodic table?
Each new period is another full shell of electrons
Are most elements non-metals?
No
What charge ions do metals form?
Positive
Do non-metals generally from positive ions?
No
Does the electron structure affect how the atom will react?
Yes
How do atoms generally react to form?
A full outer shell
How do atoms from a full outer shell?
- Losing
- Gaining
- Sharing
If the outer shell is close to being shell how is an ion formed?
By getting to a full outer shell
Do all metals have a metallic bonding?
Yes
Are metals malleable?
yes
What does malleable mean?
Can be bent or hammered into shape
Are metals strong?
Yes
Are metals good at conducting heat and electricity?
Yes
Do metals have a low melting or boiling point?
No neither
Do non-metals have metallic bonding?
No
What do non-metals tend to look like?
- Dull looing
- More brittle
Do non-metals generally conduct electricity?
No
Do non-metals generally have a lower density?
Yes
What groups are transition metals in?
2 & 3
Are transition metals in the left right or middle of the periodic table?
Middle
Are transition metals good conductors?
Yes
Are transition metals dense?
Yes
Are transition metals strong?
Yes
Are transition metals shiny?
Yes
Can transition metals only have one ion?
No
Are transition metals often structured?
Yes
Do transition metals often make good catalysts?
Yes
What is a catalyst?
Something that speeds up a reaction
Is group one acid or alkali?
alkali
Are group one metals reactive for metals?
Yes
What are the alkali metals?
- Lithium
- Sodium
- Potassium
- Rubidium
- Caesium
- Francium
How many electrons do group one metals have in their outer shell?
One
Are group one metals rough?
No, they are soft
What type of density do alkali metals have?
Low
What are the trends of group one metals as you go down the group?
- Increasing reactivity
- Lower melting and boiling points
- Higher relative atomic mass
What type of ions do alkali metals form?
Ionic compounds with non-metals
What charge do group one ions form?
+1
What do ionic compounds look like?
White solid
What do ionic compounds form when they dissolve in water?
Colourless solutions?
Do ionic compounds dissolve in water?
Yes
What do group one metals from with water?
Hydrogen gas and metal hydroxides
What are metal hydroxides?
Salts that dissolve in water to produce alkaline
The more reactive the group one metal the more violent the reaction: True/False
True
What does the amount of energy of during a reaction tell you anything about the group?
The amount if energy given of during a reaction as you go down the group
Metal + water ->
Metal hydroxide + hydrogen
What do group one metals do while reacting with chlorine gas?
React vigorously
Metal + Chlorine->
Metal chloride
Metal react with chlorine gas to form…?
White metal chloride salts
What do group one metals react with oxygen to form?
Metal oxides
What does sodium react with oxygen to form?
A mixture of sodium oxide and sodium peroxide
What does potassium react with oxygen to form?
A mixture potassium peroxide and potassium superoxide
Do group one metals have similar properties to transition metals?
No
Which is more reactive transition metals or group one metals?
Group one
Are transition metals less dense, strong and hard than group one metals?
No
Who has a lower melting point group one metals or transition metals?
Group one metals
What is manganese’s melting point?
2000 degrees Celsius
What is the boiling point of sodium?
98 degrees Celsius
What are group 7 metals called?
The halogens
Are any of the halogens metals?
No
Is fluorine very reactive?
Yes
What colour is fluorine?
Yellow
Is fluorine harmless?
No, it is poisonous
What state is fluorine?
Gas
Is chlorine non reactive?
No, it is fairly reactive
What state is chlorine
Dense gas
Is chlorine harmful?
Yes it is poisonous
Is bromine dense?
Yes
Is bromine poisonous?
Yes
What colour is bromine?
Red-brown volatile
What state is bromine?
Liqued
What is one colour and state is iodine?
Dark grey and crystalline solid or purple vapour
Are any of the halogens molecules?
All of them
What happens when you go down group 7?
- Become less reactive- it’s harder to gain an extra electron, because the outer shell’s further from the nucleus.
- Have higher melting and boiling points.
- Have higher relative atomic masses.
Do group 7 elements react very differently to each other?
No
Why do group 7 elements all react similarly?
Because they all have seven electrons in their outer shell
Can halogens form molecular compounds?
Yes
Halogen atoms can share electron via…
Covalent bonding
Why do group 7 elements react with non-metals?
In order to achieve a full outer shell
Do compounds that form halogens have a complex molecular structures?
No, they are simple
What do halogens form with ionic bonds?
Metals
What is the charge of halogens ions?
-1
What are the halogen ions called?
Halides
What type of structure do halogen compounds have?
Ionic structures
What will more reactive halogens do to less reactive ones?
They displace
What are group 7 elements called?
Noble gases
What is the colour of group 0 elements?
Colourless
How many electrons are in the outer shell of the noble gasses (apart from helium)?
8
Are the noble gasses reactive?
No
Are noble gasses monatomic gases?
Yes
What state are group 0 at room temperature?
Gasses
Are noble gasses flammable?
No
Are their properties patterns in the noble gasses?
Yes
Does the boiling point go up or down as you go down group 0?
Up
Why does the boiling point go up as you go down noble gasses?
Due to an increase in the number of electrons in each atom leading to greater intermolecular forces between which need to overcome. There’s more on intermolecular forces for small molecules
What is an atom
An atom is the smallest part of an element what can exist
Elements can be classified into two groups based on
their properties; what are these groups
Metals and non-metals
Elements may combine through chemical reactions
to form new products; what are these new
substances called?
Compounds
Do compounds have the same properties as their
constituent elements
No, they have different properties
What is a mixture? Does it have the same chemical
properties as its constituent materials
A mixture consists of two or more elements or compounds not chemically
combined together; it does have the same chemical properties
What are the methods through which mixtures
can be separated (there are five)? Do these
involve chemical reactions
Filtration, crystallisation, simple distillation, fractional distillation and
chromatography; they do not involve chemical reactions
Describe and explain simple distillation
Simple distillation is used to separate liquid from a solution – the liquid
boils off and condenses in the condenser. The thermometer will read the
boiling point of the pure liquid. Contrary to evaporation, we get to keep the
liquid.
Describe and explain crystallisation/evaporation
Evaporation is a technique for separation of a solid dissolved in a solvent from a
solvent (e.g. salt from H2O).
The solution is heated until all the solvent evaporates; the solids stays in the vessel.
Crystallisation is similar, but we only remove some of the solvent by evaporation to
form a saturated solution (the one where no more solid can be dissolved). Then,
we cool down the solution. As we do it, the solid starts to crystallise, as it becomes
less soluble at lower temperatures. The crystals can be collected and separated
from the solvent via filtration.
Describe and explain fractional distillation
Fractional distillation is a technique for separation of a mixture of liquids.
It works when liquids have different boiling points.
The apparatus is similar to the one of simple distillation apparatus, with the
additional fractionating column placed on top of the heated flask.
The fractionating column contains glass beads. It helps to separate the compounds.
In industry, mixtures are repeatedly condensed and vapourised. The column is hot at
the bottom and cold at the top. The liquids will condense at different heights of the
Describe and explain filtration
Filtration is used to separate an insoluble solid is suspended in a liquid.
The insoluble solid (called a residue) gets caught in the filter paper,
because the particles are too big to fit through the holes in the paper.
The filtrate is the substance that comes through the filter paper.
Apparatus: filter paper + funnel.
Describe and explain chromatography
Chromatography is used to separate a mixture of substances dissolved in a solvent.
In paper chromatography, we place a piece of paper with a spot containing a mixture
in a beaker with some solvent. The bottom of the paper has to be in contact with
the solvent. The solvent level will slowly start to rise, thus separating the spot
(mixture) into few spots (components).
What is a separating funnel?
A separatory funnel is an apparatus for separating immiscible liquids.
Two immiscible liquids of different densities will form two distinct layers in
the separatory funnel.
We can run off the bottom layer (the liquid with greater density) to a
separate vessel.
Describe the plum-pudding model
The atom is a ball of positive charge with negative electron embedded in
it.
Describe the Bohr/nuclear model and how it
came about
The nuclear model suggests that electrons orbit the nucleus at specific
distances (shells) – it came about from the alpha scattering experiments
Later experiments led to the discovery of
smaller, positive particles in the nucleus; what
are these particles called?
Protons
What did the work of James Chadwick provide
evidence for
The existence of neutrons in the nucleus
Describe the structure of an atom
The atom has a small central nucleus (made up of protons and neutrons)
around which there are electrons
State the relative masses and relative charges
of the proton, neutron and electron
Masses: 1, 1, very small ; Charges: 1, 0 , -1 (respectively)
Explain why atoms are electrically neutral.
They have the same number of electrons and protons
What is the radius of an atom
0.1 nm
What is the radius of a nucleus and what is it
compared to that of the atom?
1 x 10-14 m and 1/10 000
What name is given to the number of protons in
the nucleus
Atomic number
Atoms of the same element have the same
number of which particle in the nucleus?
Protons
Where is the majority of mass of an atom?
The nucleus
What is the mass number?
The total number of protons and neutrons
How does one calculate the number of neutrons
using mass number and atomic number
Subtract the atomic number from the mass number
What is an isotope? Do isotopes of a certain
element have the same chemical properties?
Atoms of the same element (same proton number) that have a different
number of neutrons.
They have the same chemical properties as they have the same
electronic structure
What is the relative atomic mass
The average mass value which takes the mass and abundance of isotopes
of an element into account, on a scale where the mass of 12C is 12.
He, Be, F, Na, Ca configurations (respectively):
2 2,2 2,7 2,8,1 2,8,8,2
What are ions
Ions are charged particles. They are formed when atoms lose electrons
(positive ions) or gain (negative ions) electrons.
E.g. sodium positive ion, Na+
, has an electronic configuration of 2,8 (same
as Ne). An atom of sodium has lost one electron.
What is formed when a metal reacts with a
non-metal?
An ionic compound (made of positive and negative ions).
What is formed when a non-metal reacts with a
non-metal?
A molecular compound containing covalently bonded atoms.
Atoms share electrons, as opposed to transferring electrons between
each other (cf. ionic compounds).
Explain the following: solute, solvent, solution,
miscible, immiscible, soluble, insoluble.
A solute is a substance that is dissolved in a solvent. Together, they form a
solution.
Miscible refers to the substances (particularly liquids) that mix together, e.g. water
and alcohol. Water and oil are immiscible, i.e. they do not mix.
Soluble refers to the substance that can be dissolved in a solvent, e.g. salt in
water. Insoluble substance won’t dissolve in a particular solvent.
The columns of the periodic table are called?
Groups
The rows of the periodic table are called…?
Periods
Are elements in the same
group similar or different
They may have similar chemical properties, as they have the same
number of outer shell electrons.
In terms of energy levels, what are the
differences between elements of the same
period?
They have the same number of energy levels
Electrons occupy particular energy levels, with each
electron in an atom at a particular energy level; which
available energy level do electrons occupy?
The lowest available energy level
The elements of Group 0 are more commonly
known as…?
The noble gases
What makes the periodic
table periodic?
Similar properties of elements occur at regular intervals
Elements in the same group have the same
number of electrons in their outer shell; what
does this tell us about their chemical properties?
They have similar chemical properties
In terms of shells, what is the difference
between elements in the same period?
They have the same number of shells
What change in shell number is seen as one
moves down a group?
The number of shells increases
Early periodic tables were incomplete and
elements were placed in inappropriate groups if
what was to be followed?
The strict order of atomic weights
Knowledge of what made it possible to explain
why the order based on atomic weights was not
always correct?
Isotopes
Mendeleev overcame some problems with the
table by doing what? He also changed the order
of some elements based on what
Leaving gaps; atomic weights
The majority of elements are…?
Metals
Elements that react to form positive ions are…?
Metals
Elements that do not form positive ions are…?
Non-metals
Elements in Group 1 are known as…?
The alkali metals
State three characteristics of the Alkali Metals
All have one electron in their outer shell; have low density; are stored
under oil (to prevent reactions with oxygen or water); are soft (can be cut
with knife)
How do Group 1 elements react with
non-metals? Why are these reactions similar for
the different Group 1 elements?
They form ionic compounds which are soluble white solids which form
colourless solutions – they all have one electron in their outer shell.
How do Group 1 elements react with water?
They release hydrogen and form hydroxides which dissolve to form
alkaline solutions; react vigorously with water fizzing and moving around
on the surface of the water.
How does reactivity change moving down Group
1? Why?
Reactivity increases as the atoms get larger and the distance between
the nucleus and the outer electrons increases and thus attraction from the
nucleus decreases, allowing them to more easily lose electrons.
State five characteristics of Group 7
- 7 electrons in outer shell
- Coloured vapours
- Diatomic molecules
- Form ionic salts with metals
- Form molecular compounds with non-metals
State five State Group 7 elements and states of
matter of molecules they form
- Fluorine, F. F2 is a pale yellow gas. - Chlorine, Cl. Cl2 is a pale green gas. - Bromine, Br. Br2 is dark brown liquid - Iodine, I. I2 is a grey solid.
State three changes that occur in Group 7 as
one moves down the group
- Higher relative molecular mass
- Higher melting and boiling point
- Less reactive – less easily gain electrons
A more reactive halogen displaces a less reactive one from
an aqueous solution of its salt; write the equations and state
the colour change seen when chlorine reacts with sodium
bromide and when chlorine/bromine reacts with sodium
iodide.
2 \+ 2 NaBr → Br2 \+ 2 NaCl, or Cl2 \+ 2Br– → Br2 \+ 2 Cl– ; in this reaction, an orange colour of Br2 would appear
Cl2 \+ 2 NaI → I2 \+ 2 NaCl, or Cl2 \+ 2I– → I2 \+ 2 Cl– Br2 \+ 2 NaI → I2 \+ 2 NaBr, or Br2 \+ 2I– → I2+ 2 Br– ; in these two reactions, a brown colour of I2 would appear
A more reactive halogen displaces a less
reactive one from an aqueous solution of its salt;
explain the trend in reactivity of halogens in these
reactions
Reactivity decreases down the group. As we go down the group, the atoms
get larger, so an incoming electron will be less tightly held by the attractive forces
from the nucleus. That’s why Cl2
displaces Br–
and I–
.
Compare group 1 metals with transition metals
Group 1 metals and transition metals are heat and electricity conductors.
They are shiny when polished and form ionic compounds with non metals.
Transition metals have higher densities and higher melting points than Group
1 metals. They are less reactive and harder than Group 1 metals.
State three common characteristics of transition
metals
- Ions with different charges
- Coloured compounds
- Catalytic properties
What is a catalyst?
A catalyst is a chemical substance that increases the rate of a
chemical reaction.
It is not used up over the course of the reaction.
State the colours of flames observed when lithium,
sodium, and potassium burn in oxygen
Crimson-red, Li
Yellow-orange, Na
Lilac, K
