Unit 1 - Atomic structure and periodic table

Question 1

What do chemical reactions cause atoms to do?

Answer 1

Chemical reactions cause atoms to change what they’re bonded to.

Question 2

What is an element?

Answer 2

A substance containing only one type of atom, such as Oxygen.

Question 3

What is a compound?

Answer 3

A substance containing 2 or more different types of atoms that are chemically bonded, such as H2O

Question 4

What is the conservation of mass?

Answer 4

Atoms can neither be created or destroyed in a reaction, so equations must be balanced (mass of reactants = mass of products)

Question 5

What should you start with when balancing equations?

Answer 5

Balance atoms in a compound first, then elements.

Question 6

What is a mixture?

Answer 6

Different substances that are not chemically bonded e.g. solutions

Question 7

What is a solute?

Answer 7

A substance that dissolves in the solvent to form a solution.

Question 8

What are the separation techniques?

Answer 8

-Filtration
-Evaporation
-Distillation
-Chromatography

Question 9

How does filtration work?

Answer 9

Removes large, insoluble particles from a liquid e.g. sand from water

Question 10

How does evaporation work?

Answer 10

Leaves behind crystals of a dissolved substance (solute) if heated gently (crystallisation)

Question 11

How does distillation work?

Answer 11

Condensing the evaporated solvent and collecting it. Fractional distillation can separate liquids due to different boiling points.

Question 12

How does chromatography work?

Answer 12

Causes substances to rise up paper due to capillary action. Lighter particles move further up the chromatography paper (stationary phase)

Question 13

What is the structure of a solid?

Answer 13

-Particles in regular arrangements
-Vibrate around fixed positions
-Cannot be compressed

Question 14

What is the structure of a liquid?

Answer 14

-Particles have no regular arrangements
-Particles can move past each other
-cannot be compressed

Question 15

What is the structure of a gas?

Answer 15

-Particles are far apart
-Particles move randomly at high seeds (they have high energy)
-Can be compressed

Question 16

How does melting/evaporating work?

Answer 16

Energy in the form of heat is needed to overcome the electrostatic forces of attraction between particles to melt/evaporate

Question 17

What type of change is melting/evaporating?

Answer 17

Physical change as no new substance has been made.

Question 18

What is the order of who progressed the theory of atomic structure?

Answer 18

-John Dalton
-JJ Thomson
-Ernest Rutherford
-Niels Bohr
-James Chadwick

Question 19

What did John Dalton discover?

Answer 19

John Dalton firs suggested atomic theory, that all matter was comprised of invisible and inseparable particles called atoms

Question 20

What did JJ Thomson discover?

Answer 20

JJ Thomson discovered the electron and later created the ‘plum pudding’ model where electrons were embedded in an overall positive structure.

Question 21

What did Ernest Rutherford discover?

Answer 21

Ernest Rutherford, through the gold foil experiment, concluded that the atom contained a centre of positive charge called the nucleus. He also concluded that the atom was mainly empty space. The fact that a very small number of alpha particles came straight back suggests the nucleus was tiny

Question 22

What did Niels Bohr discover?

Answer 22

Niels Bohr deduced that electrons orbited the nucleus in shells

Question 23

What did James Chadwick discover?

Answer 23

James Chadwick discovered that the atom contained neutrons as well as protons.

Question 24

What does the atomic number of an element show?

Answer 24

Atomic number (bottom number) shows the number of protons in a nucleus for one atom. Therefore, an atom must also have the same number of electrons to be neutral, or else it would be an ion.

Question 25

What does the mass number/relative atomic mass of an element show?

Answer 25

Mass number (Ar) shows the number of protons and neutrons in the nucleus of an atom.

Question 26

What is an isotope?

Answer 26

Atoms of an element with the same number of protons but a different number of neutrons

Question 27

How were atoms ordered on previous versions of the atomic table?

Answer 27

In order of atomic weight, then also grouped together if they had similar properties

Question 28

What did Mendeleev do?

Answer 28

He grouped the elements based on properties, even if the order didn't follow atomic weight. His table had gaps in, which he predicted were elements yet to be discovered. He was largely correct.

Question 29

What do metals do?

Answer 29

Always donate electrons to gain an empty outer shell, forming positive ions.

Question 30

What do non-metals do?

Answer 30

Always accept electrons to gain a full outer shell. They can form negative ions or share electrons to do this.

Question 31

What is group 1?

Answer 31

Alkali metals (react with water to produce an alkali). They all lose/donate their outer electron so their ions are all +1. They get more reactive down the group.

Question 32

Why do alkali metals get more reactive down the group?

Answer 32

Number of shells increase, meaning the distance increases between the electrons and nucleus so the electrostatic forces weaken, meaning the electron is more readily donated.

Question 33

What is group 7?

Answer 33

Halogens - form -1 ions as they gain 1 electron for a full outer shell. They get less reactive down the group, and boiling point increases.

Question 34

What is group 0/8?

Answer 34

Noble gases - very unreactive as they already have an full outer shell.

Question 35

What is special about transition metals?

Answer 35

They can donate different numbers of electrons, e.g. Iron (II) = Fe2+. They are generally harder and less reactive than alkali metals, also forming coloured compounds.