Unit 1:Atomic structure and the periodic table

Question 1

What are atoms?

Answer 1

The smallest part of an element that can exist.

They make up everything

Question 2

What is an element?
what is a compound?
what is a mixture?

Answer 2

a substance made up of one type of atom
two or more different types of atom chemically bonded together.
Two or more different types of atom or compound not chemically bonded together

Question 3

what is the word equation for the reaction when you burn magnesium?
what is the symbol equation for this?

Answer 3

magnesium + oxygen → magnesium oxide

2Mg + O2 → 2MgO

Question 4

what are the 4 main techniques used when separating mixtures and when should you use them?

Answer 4

Filtration - to separate insoluble solids from liquids
Crystallisation - to separate soluble solids from liquids ( you could also use evaporation for this)
Simple Distillation - to separate solutions
Fractional Distillation - to separate a mixture of liquids

Question 5

when was the atom first thought of

Answer 5

5th century BC, Democritus thought that all matter was made of identical lumps called “atomos”

Question 6

when and why was the plum pudding model of the atom developed?

Answer 6

in the early 18th century, J.J. Thompson discovered the electron so decided that atoms were spheres of positive charge with electrons stuck in them

Question 7

when and how did Rutherford prove the plum pudding model wrong?

Answer 7

In 1909 he fired a beam of positive alpha particles at thin gold foil and measured where they would come out on the other side. Based off the plum pudding model they assumed that most of the particle would go through and only be slightly deflected. However, some were deflected back. This showed that the mass of the positive part of the atom was concentrated in a small area, not spread out.

Question 8

What did Niels Bohr suggest about the structure of the atom?

Answer 8

He said that the electrons orbiting the nucleus do so at different distances called energy levels.

Question 9

What did James Chadwick add to the atom model and when did he do it

Answer 9

in 1932 he proved the existence of the neutron, explaining the imbalance between the atomic and mass number

Question 10

describe the charges of:
a proton
a neutron
an electron
an atom

Answer 10

proton: +1
neutron: 0
electron: -1
atom: 0

Question 11

state the relative masses of:
a proton
a neutron
an electron

Answer 11

proton: 1
neutron: 1
electron: almost 0

Question 12

describe the distribution of mass in an atom

Answer 12

almost all of it is concentrated in the centre, the nucleus

Question 13

state the number of:
protons
neutrons
electrons
in a sodium atom

Answer 13

protons: 11
neutrons: 12
electrons: 11

Question 14

What are isotopes

Answer 14

they are atoms of the same element but with different amounts of neutrons

Question 15

what is relative atomic mass?

Answer 15

It is the average mass of the atoms in an element taking into account different masses and abundances of isotopes.

Question 16

what is the equation for relative atomic mass?

Answer 16

((isotope abundance x isotope mass number)+ (other isotope’s abundance x isotope mass))/sum of all isotope abundances

Question 17

What are electron shells also known as

Answer 17

energy levels

Question 18

Which energy levels are always filled first

Answer 18

the lowest ones

Question 19

how many electrons are allowed in:
the 1st shell
the 2nd shell
the 3rd shell
the 10th shell

Answer 19

1st shell : 2
2nd shell : 8
3rd shell : 8
10th shell : 8

Question 20

How are electron configurations generally represented?

Answer 20

dot and cross diagrams

Question 21

how are the elements in the periodic table arranged?

Answer 21

they are arranged by their relative atomic mass and properties

Question 22

how are elements with similar properties placed in the periodic table?

Answer 22

If they have similar properties they would be placed in the same group (column)

Question 23

why do elements in the same group have similar properties?

Answer 23

they all have the same number of electrons in their outer shell

Question 24

how is the reactivity of elements in groups 1 and 7 related to their position in the periodic table?

Answer 24

as you go down the elements in group 1, reactivity increases.
as you go down the elements in group 7, reactivity decreases

Question 25

how were periodic tables in the early 1800s arranged?

Answer 25

in order of atomic mass

Question 26

How and when did Dimitri Mendeleev arrange the periodic table

Answer 26

in 1869 he arranged the elements in order of atomic mass but also by their properties

Question 27

What did Mendeleev’s periodic table allow him to do?

Answer 27

It allowed him to predict what some of the properties of undiscovered elements would be

Question 28

where are the non-metals found on a periodic table?

Answer 28

on the right side

Question 29

what are the differences between metals and non-metals?

Answer 29

metals generally don’t form negative ions when they react, unlike non-metals
metals are strong but malleable, non-metals are brittle
metals are great heat and electrical conductors, non-metals generally don’t conduct electricity

Question 30

why are non-metals to the right of the periodic table?

Answer 30

they all have lots of electrons in their outer shell, which is why they are in higher groups than most of the metals, which have few electrons in their outer shells

Question 31

Describe the group 0 elements and their properties

Answer 31

Also known as noble gases, the group 0 elements are all inert, colourless gases. As you move down the group, the boiling point increases. They aren’t flammable as they are inert.

Question 32

why are noble gases unreactive?

Answer 32

they all have full outer shells, so are stable and don’t need to react with other elements and form ions

Question 33

describe the group 1 elements and their properties

Answer 33

also known as alkali metals, the group 1 elements are soft, reactive metals. As you move down the group, the reactivity increases. They are soft and have a low density

Question 34

why are alkali metals so reactive?

Answer 34

They all have 1 electron in their outer shell, meaning it’s very easy to ionise them and cause a reaction, especially those lower down in the group that have many shells, meaning the outermost electron shell isn’t pulled in by the nucleus that strongly, making it even easier to cause a reaction

Question 35

describe group 7 elements and their properties

Answer 35

also known as halogens, the group 7 elements are non-metal coloured vapours. As you move down the group, the reactivity decreases and the melting and boiling point increase

Question 36

why do halogens have the trends in reactivity and boiling/melting points that they do

Answer 36

They get less reactive as you go down as it’s harder to gain an extra electron as the outer shell is further from the nucleus.
Because of this, less energy will be needed to break the intermolecular bonds in the upper halogens then the lower ones, therefore the halogens lower in the group have a higher boiling/melting point

Question 37

how do halogens react with non-metals?

Answer 37

Halogens form covalent bonds when reacting with non-metals, for example phosphorus and chlorine react to form phosphorus chloride.

Question 38

how do halogens react with metals?

Answer 38

halogens react with metals to from ionic bonds, for example sodium and chlorine react to make sodium chloride