4.4.1.1 The Structure of an Atom

Question 1

Size and radius of atoms:

Answer 1

• atoms are very small
• radius of about 1 x 10⁻¹⁰ metres

Question 2

What is the basic structure of an atom?

Answer 2

• positively charged nucleus made up of protons and neutrons
• nucleus surrounded by negatively charged electrons

Question 3

What is the radius of a nucleus compared to the radius of an atom?

Answer 3

radius of a nucleus is less than 1/10,000 of the radius of atom

Question 4

Where is most of the mass of an atom concentrated?

Answer 4

most of the mass of an atom is concentrated in the nucelus

Question 5

What is the electron arrangement of an atom?

Answer 5

• the electrons are arranged at different distances from the nucleus in energy levels
• the electrons orbit the nucleus in the shells

Question 6

Why might the electron arrangement of an atom change?

Answer 6

• electron arrangement may change with the absorption of electromangentic radiation (move further from nucleus; higher energy level - due to having more energy)
• or by the emission of EM radiation (move closer to nucleus; lower energy level - due to loss of energy)