Atomic Structure - Atoms And Isotopes

Question 1

Give an approximation of the radius of an atom.

Answer 1

1x 10 to the power of -10m

Question 2

What are the three subatomic constituents of an atom?

Answer 2

1. Proton
2. Neutron
3. Electron

Question 3

Where is the most of the mass of an atom concentrated?

Answer 3

In the nucleus

Question 4

Approximately what proportion of the total radius an atom is the nucleus?

Answer 4

1/10,000

Question 5

Describe the arrangement of protons, neutrons and electrons in an atom.

Answer 5

• The protons and neutrons are found in the atom’s
nucleus.
•The electrons are found in discrete energy levels around the nucleus.

Question 6

What type of charge does the nucleus of an atom have? Why?

Answer 6

• Positive charge
• Protons have a positive charge
• Neutrons have no charge

Question 7

GIve two ways an atom’s electron arrangement can be changed and what happens.

Answer 7

1. Absorbing electromagnetic radiation - electrons move to a higher energy level, moves further away from the nucleus.
2. Emitting electromagnetic radiation - electrons closer to the nucleus, they move to a lower energy level.

Question 8

How does the ratio of electrons to protons in an atom result in the atom having no overall charge?

Answer 8

• The no. of protons is equal to the no. of electrons
• Protons and electrons have equal and opposite
charges, so charge cancels out

Question 9

What do all forms of the same element have in common?

Answer 9

They all have the same no. of protons.

Question 10

What is the name given to the no.of protons in an atom?

Answer 10

Atomic number.

Question 11

What is atonic mass number?

Answer 11

The total no. of protons and neutrons in the atom.

Question 12

How do atoms turn into positive ions?

Answer 12

• Lose one or more of their outer shell electrons.
Electrons are negatively charged so taking son or
more away will result in a positively charged ion.

Question 13

What may lead to a scientific model being changed or replaced?

Answer 13

The discovery of new experimental evidence which doesn’t agree with the existing theory.

Question 14

How did the plum-pudding model describe the atom?

Answer 14

A ball of positive charge, with negatively charged electrons distributed evenly throughout it.

Question 15

Prior to the discovery of the electron what was believed about the atom?

Answer 15

The atom was believed to be indivisible.

Question 16

Which experiment led to the plum-pudding model being discovered?

Answer 16

Rutherford’s alpha-scattering experiment.

Question 17

What is the name of the currently accepted model of the atom?

Answer 17

The Bohr nuclear model.

Question 18

State the conclusion of the Alpha-Scattering experiment.

Answer 18

• Most of the mass of the atom is concentrated at the center, in the nucleus .
• The nucleus in positively charged.

Question 19

What reinforces a scientific theory?

Answer 19

When experimental results agree with the hypothesised theoretical calculations and theories.

Question 20

What did James Chadwick’s experiment on the atom prove?

Answer 20

The existence of neutrons.