Year 9 Revision and recap 1 chemistry

Revision and recap

• Definitions

• Atomic structure

• The periodic table

• Electron configuration

• Radioactivity

• Conservation of mass

• Chemical reactions

• Balancing equations

Content covered so far

Key definitions

Chemistry uses words that can be confusing or difficult to understand. Key words such as, atom, compound, element, ion, mixture, molecule are used throughout.

Match

Match the following terms with their definitions

• Atom

• Compound

• Element

• Cation

• Anion

The fundamental building block of all materials. It consists of protons, neutrons, and electrons.

A pure substance that is made up of 2 or more different types of atoms chemically joined.

A substance made up of only 1 type of atom.

A positively charged ion.

A negatively charged ion.

• The fundamental building block of all materials. It consists of protons, neutrons, and electrons.

• A pure substance that is made up of 2 or more different types of atoms chemically joined.

• A substance made up of only 1 type of atom.

• A positively charged ion.

• A negatively charged ion.

Atomic structure

The atomic structure of an atom is made up of 3 subatomic particles:
- Electrons
- Protons
- Neutrons

Labelling

Label the following atomic structure

Drag labels to their correct position on the image

Protons

Neutrons

Electrons

Open Ended

What type of charge does a proton have?

Multiple Choice

How many protons does an atom have if it has an atomic number of 15?

• 30

• 15

• 16

• 18

The periodic table

The periodic table provides us with information about the elements.
- Atomic number
- Element symbol
- Element name
- Atomic mass

Match

Match the following element names to their symbols

• Iron

• Copper

• Potassium

• Phosphorus

• Calcium

Fe

Cu

K

P

Ca

• Fe

• Cu

• K

• P

• Ca

Match

Match the following elements to their atomic number

• Boron

• Chlorine

• Sodium

• Argon

• Sulphur

5

17

11

18

16

• 5

• 17

• 11

• 18

• 16

Open Ended

Aluminium has an atomic mass of 27, and has 13 protons. How many neutrons does it have?

Electron configuration

The electron configuration of an element allows for us to identify how many electrons it has as well as its capabilities of bonding with another element.

The example shows the calcium atom's electron configuration. How many electrons does it have?

There are rules to follow when drawing electron shell diagrams:
- Each orbital has a maximum number of electrons it can hold.


1st orbital - 2
2nd orbital - 8
3rd orbital - 8
4th orbital - 18




- Think of the bus seat rule - each electron from the 2nd shell onwards wants an electron buddy next to them.
- The number of electrons should be the same as the atomic number

Draw

Draw the electron shell configuration for Neon

Multiple Choice

What is the electron configuration for Chlorine?

• 2, 4, 7

• 2, 8, 6

• 2, 8, 7

• 2, 8

Multiple Choice

What is the electron configuration for Calcium?

• 2, 4, 4, 2

• 2, 8, 8, 1

• 2, 8, 8

• 2, 8, 8, 2

Draw

Draw the electron shell configuration for Fluorine

• positively charged ion

• Loses electrons

Cation

• A negatively charged ion

• Gains electrons
  

Anion

Ions

Match

Match the following ions

• Chloride

• Potassium

• Oxide

• Magnesium

• Bromide

Cl^-

K⁺

O^2-

Mg²⁺

Br^-

• Cl^-

• K⁺

• O^2-

• Mg²⁺

• Br^-

Radioactivity

Isotopes are members of a family of an element that all have the same number of protons but different numbers of neutrons.

Some elements will have different number of neutrons and therefore, will go via alternative names. For example, Carbon-12, Carbon-13, and Carbon-14

Multiple Choice

How many neutrons does carbon-14 have

• 12

• 6

• 8

• 7

Multiple Choice

How many neutrons does hydrogen-3 (tritium) have?

• 1

• 0

• 3

• 2

Chemical reactions

Synthesis

When 2 or more single elements react to form 1 product.

A + B -> AB

Example: 2Mg + O₂ -> 2MgO

Chemical reactions

Decomposition

When a compound breakdown into 2 or more simpler products.
AB -> A + B
Example: H₂CO₃ -> CO₂ + H₂O

Chemical reactions

Single replacement

When a single element replaces another element in a compound
A + BC -> AC + B
Example: Zn + CuCl₂ -> ZnCl₂ + Cu

Chemical reactions

Double replacement

The cations and anions of two compounds switch places
AB + CD -> AC + BD
Example: HCl + NaOH -> NaCl + H₂O

Multiple Choice

What type of reaction is the following chemical reaction?

KBr + AgNO₃ -> KNO₃ + AgBr

• Synthesis

• Decomposition

• Single replacement

• Double replacement

Multiple Choice

What type of reaction is the following chemical reaction?

Cu + 2HCl -> CuCl₂ + H₂

• Synthesis

• Decomposition

• Single replacement

• Double replacement

Multiple Choice

What type of reaction is the following chemical reaction?

2H₂ + O₂ -> 2H₂O

• Synthesis

• Decomposition

• Single replacement

• Double replacement

Multiple Choice

What type of reaction is the following chemical reaction?

2HgO -> 2Hg + O₂

• Synthesis

• Decomposition

• Single replacement

• Double replacement

Balancing equations

Conservation of mass

The conservation of mass states that mass is neither created nor lost during chemical reactions.

This is important to remember when balancing equations...

Balancing equations

Word equations

Word equations are the reactants -> products of a chemical reaction written in word format.

EXAMPLE:
Hydrogen + Oxygen -> Water

Open Ended

Write the word equation for the following reaction:

sodium oxide reacts with hydrochloric acid to produce sodium chloride and water

Drag and Drop

For the following equation, fill in the blanks for to balance the equation:

​

Placeholder

H₂ + O₂ -> ​

Placeholder

H₂O

Drag these tiles and drop them in the correct blank above

2

3

4

Drag and Drop

For the following equation, fill in the blanks for to balance the equation:

​ ​

Placeholder

+ ​ H₂SO₄ -> CuSO₄ + H₂O

Drag these tiles and drop them in the correct blank above

CuO

CuO2

OCu

Drag and Drop

For the following equation, fill in the blanks for to balance the equation:

​

Placeholder

​ ​ H₂O₂ -> ​

Placeholder

H₂O + ​

Placeholder

O₂

Drag these tiles and drop them in the correct blank above

2

1

Drag and Drop

For the following equation, fill in the blanks for to balance the equation:

​

Placeholder

​ N₂ + ​

Placeholder

H₂ -> ​

Placeholder

NH₃

Drag these tiles and drop them in the correct blank above

1

3

2