Atomic Structure

An atom consists of three basic types of par-ticles.

What are the three types of particles in an atom?

The electron, which is negative, the positive proton and the neutral neutron.

Which of the above particles are in the nucleus of an atom?

The protons and the neutron reside in the nucleus of the atom.

What is a nucleon? It is either a proton or a neutron.

What is nucleon number? It is the sum of the number of protons and

neutrons in an atom.

What is another name for nucleon number?

Mass number.

What is proton number? It is the number of protons in the atom.

What is another name for proton number? Atomic number.

An atom of any element is represented by AZ

X.

What is A? Mass or nucleon number.

What is Z? Atomic or proton number.

What is X? Symbol of the element.

What are isotopes? Isotopes of an element are atoms that have

the same proton number and different nucleon numbers.

Write down the isotopes of hydrogen. Isotopes of hydrogen include 1H, 2H and

3H. They all have atomic number of 1.

Complete the following table using the applet.

Teachers guide

Symbol Name

Au

Silver

Gold

Z

47

79

A

108

197

N

61

118

Ca

Cu

Calcium

Copper

20

29

40

64

20

35

Ne

Mg

Neon

Magnesium

10

12

20

24

10

12

O

Pb

Oxygen

Lead

8

82

16

207

8

125

Si

Ti

Silicon

Titanium

14

22

28

48

14

26

Ag

U

Zn

Uranium

Zinc

92

30

238

65

146

35

N = Number of neutrons