9 Chemistry Revision

Atomic Structure

100

Subatomic particle with positive charge

Proton

200

Subatomic particle with negative charge

Electron

300

Subatomic particle with neutral/no charge

Neutron

400

How many electrons can fit into the second shell?

8

500

Write the electron configuration for chlorine

2.8.7

Periodic Table

100

What is the atomic number of hydrogen?

1

200

What is the atomic mass of oxygen?

16 amu

300

How do you determine the number of electrons in an atom from the periodic table?

Same as atomic number (number of protons)

400

How do you determine number of neutrons from the periodic table?

Atomic mass - atomic number = neutrons

500

Explain why noble gases are unreactive.

They have full valence shells

Isotopes & Decay

100

Define an isotope.

Same element, different number of neutrons.

200

Name 2 isotopes of carbon-12.

Carbon-13, Carbon-14

300

What is a half-life?

The amount of time it takes for half of a substance to undergo radioactive decay

400

Explain the process of alpha decay, including why and what happens

Alpha decay occurs when the nucleus of an isotope is too heavy

It will emit a helium nucleus to stabilise

The atomic number will decrease by 2 and atomic mass decrease by 4

500

Explain the process of beta decay, including why and what happens

Beta decay occurs when there are too many neutrons in the nucleus

It will convert a neutron to a proton and emit an electron

The atomic number will increase by 1 and atomic mass will not change

Ions

100

Define an ion

Same element, different number of electrons 

200

What is a cation?

Positively charged ion (lost electrons)

300

What is an anion?

A negatively charged ion (gained electrons)

400

How does the electron configuration of a sodium ion differ from that of a sodium atom?

Sodium⁺ ion: 2.8 (lost 1 electron)

Sodium atom: 2.8.1

500

Explain why ions bond to form compounds

Ions bond together to stabilise by filling their valence shells.

Chemical Equations

100

If 4 grams of hydrogen reacts with 32 grams of oxygen to form water, how much water is produced?

4 g + 32 g = 36 g of water

200

Define the conservation of mass.

Matter cannot be created or destroyed

300

Balance the equation:

H₂ + O₂ -> H₂O

2H₂ + O₂ -> 2H₂O

400

Balance the equation:

CO₂ + H₂ -> CH₄ + O₂

CO₂ + 2H₂ -> CH₄ + O₂

500

Balance the equation:

C₂H₆ + O₂ -> CO₂ + H₂O

2C₂H₆ + 7O₂ -> 4CO₂ + 6H₂O