These are the specification points you need to understand ......These are the specification points...

These are the specification points you need to understand from this work

Work through the slides and copy out information into your chemistry book

when asked to.

Any problems:e.shore@bishopchalloner,bham.sch.uk

mailto:e.shore@bishopchalloner,bham.sch.uk

Mass number and atomic number

• Objectives:

• To know the structure of the atom.

• To understand what the atomic and mass number tells us about an atom.

• To understand which number identifies an element.

• To be able to work out the number of protons, neutrons and electrons in an atom.

Starter

Can you answer the questions on the

next slide?

1. Where do you find most of the mass of the

atom concentrated?

2. Which sub-atomic particles do you find in the

nucleus?

3. Where do you find the electrons?

4. What is the charge of an electron?

5. Why do you know that atoms have the same

number of protons and electrons?

1. Where do you find most of the mass of the

atom concentrated?

in the nucleus

2. Which sub-atomic particles do you find in the

nucleus?

protons and neutrons

3. Where do you find the electrons?

They orbit the nucleus in shells

4. What is the charge of an electron?

-1

5. Why do you know that atoms have the same

number of protons and electrons?

because atoms have no charge


• Objectives:





Each element in the Periodic Table has two numbers:

Copy into your book

8 of 19 © Boardworks Ltd 2011

What is mass number?

Electrons have a mass of almost zero, which means that the

mass of each atom results almost entirely from the number

of protons and neutrons in the nucleus.

mass number = number + number

of neutrons of protons

1413aluminium

43lithium

01hydrogen

neutronsprotonsatomsmass

number

27

7

1

It is the larger of the two numbers shown

in most periodic tables.

Copy into your book


• Objectives:






The atomic number

Each element has a definite and fixed number of protons.

All the atoms of a particular element always contain the

same number of protons. For example:

Atomic number = the number of protons in

an atom. This number is unique to each

element and so identifies an element.

It is the smaller of the two numbers

shown in most periodic tables.

hydrogen atoms always contain 1 proton

carbon atoms always contain 6 protons.

If the number of protons changes, then the atom becomes

a different element.


Atomic number = the number of protons in

an atom. This number is unique to each

element and so identifies an element.

It is the smaller of the two numbers

shown in most periodic tables.

If the number of protons changes, then the atom becomes

a different element.

Copy into your book


• Objectives:





What are the missing words?


protons

neutrons

electrons neutral


Fill in the missing numbers


8 8 8

30 30 35

79 79 118


mass

13

14


Fill in the missing numbers


35 35 46

20 20 20


• Now have a go at filling in the below

worksheet (separate document).The

answers are after this slide.

Use this

information to

help you fill in

the sheet.


• Answers


Knowledge check

• Can you answer the following questions?

Well done for completing week 5

chemistry.

These are the specification points you need to understand ......These are the specification points...

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