Atomic structure

Question 1

What is an atom?

Answer 1

The smallest part of an element that can exist + ALL substances are made up of atoms

Question 2

What are chemical symbols?

Answer 2

Symbols (one or two letters) to represent an atom so it can universally recognised around the world

Question 3

What is a compound?

Answer 3

A substance made up of two or more elements chemically joined together in fixed proportions

Question 4

How are compounds formed?

Answer 4

From combining two or more elements by chemical reactions. Chemical reactions always involve the formation of one or more new substances + often involve energy change

Question 5

How can compounds be separated?

Answer 5

By chemical reactions

Question 6

What is a mixture?

Answer 6

They consist of two or more elements or compounds that ARE NOT chemically combined together. The chemical properties of each substance in the mixture are UNCHANGED

Question 7

How can mixtures be separated?

Answer 7

• Filtration
• Crystallisation
• Simple distillation
• Fractional distillation
• Chromatography

Question 8

What is chromatography?

Answer 8

A method used to separate and identify the components of a mixture of soluble substances

Question 9

What is distillation?

Answer 9

A process used to separate liquids based on their boiling points

Question 10

What is filtration?

Answer 10

A process used to separate liquids from insoluble solids

Question 11

What is crystallisation?

Answer 11

A process of forming solid crystals from a solution by allowing the solvent to evaporate slowly

Question 12

What is the atomic theory + who created it?

Answer 12

It was the theory created by the Greek philosopher, Democritus, which was that everything is made up from tiny particles that CANNOT be broken down any further + are separated from each other by empty space

Question 13

What Russian scientist created the first successful periodic table?

Answer 13

Dmitri Mendeleev

Question 14

What was John Dalton’s theory?

Answer 14

In 1803, he believed that he thought that all matter was made up of tiny particles called atoms, which he imagined as tiny solid spheres that couldn’t be divided

Question 15

What was JJ Thomson’s ‘plum pudding model’?

Answer 15

He carried out experiments + discovered the electron. This led him to suggest the ‘plum pudding model’ - the atom is a ball of positive charge with negative electrons embedded in it

Question 16

What was Ernest Rutherford’s experiment + ‘nuclear model’?

Answer 16

He designed an experiment to test the plum pudding model. In the experiment, positively charged alpha particles were fired at thin gold foil. Most alpha particles went straight through the foil but a few scattered in different directions.

This led him to suggest a new model for the atom which he called the ‘nuclear model’. In the nuclear model:

• The mass of the atom is concentrated in the centre, the nucleus
• The nucleus is positively charged

Question 17

What was Niels Bohr’s model?

Answer 17

He adapted from Rutherford’s nuclear model + electrons orbit the nucleus in shells that were at a certain distance away from the nucleus

Question 18

How were protons discovered?

Answer 18

Further experiments led to the idea that the nucleus contained small particles, called protons. Each proton has a small amount of positive charge.

Question 19

What did James Chadwick discover?

Answer 19

He discovered the neutron was within the nucleus in 1932

Question 20

What is the atomic number?

Answer 20

the number of protons (and electrons) in an atom of an element (the bottom number)

Question 21

What is the same about atoms of the same element?

Answer 21

They have the same number of protons

Question 22

What is the relative charge of protons, neutrons and electrons?

Answer 22

Protons = 1

Neutron = 0

Electron = -1

Question 23

What is the number of protons equal to?

Answer 23

Number of protons = Number of electrons

Question 24

How big are atoms?

Answer 24

0.1nm + the radius of a nucleus is less than 1/10,000 of that atom, though it holds almost all the mass

Question 25

What is the mass number?

Answer 25

the total number of protons and neutrons in an atom (the top number)

Question 26

What is the relative mass of protons, neutrons + electrons?

Answer 26

Protons = 1

Neutrons = 1

Electrons = 0

Question 27

What are isotopes?

Answer 27

When atoms of the same element have different numbers of neutrons

Question 28

What is the relative atomic mass?

Answer 28

An average value that takes account of the abundance of the isotopes of the element

Question 29

How do you calculate the relative atomic mass?

Answer 29

(isotope 1 mass x abundance) + (isotope 2 mass x abundance) / 100

Question 30

What does the electronic structure of an atom tell you?

Answer 30

How many electrons are in each shell

Question 31

What is the maximum number of electrons in the first shell?

Answer 31

2

Question 32

What is the maximum number of electrons that can be in the other shells?

Answer 32

8