S 1.2

Question 1

Dalton’s theory:

Answer 1

-All matter is composed of tiny indivisible particles called atoms
-Atoms cannot be created or destroyed
-Atoms of the same element are alike in every way
-Atoms can combine together in small numbers to form molecules.
-Elements react together to form compounds.

Question 1

What did Ernest Rutherford do?

Answer 1

He fired alpha particles at a piece of gold foil. The positively charged alpha particles collide with and are repelled by the positively charged nucleus.

Question 2

What is the mass number determined by?

Answer 2

Protons + Neutrons

Question 3

What is the atomic number determined by?

Answer 3

Protons

Question 4

What is an ion?

Answer 4

Atom that has gained or lost electrons

Question 5

What do you call it when an atom loses electrons?

Answer 5

Cation

Question 6

What do you call it when an atom gains electrons?

Answer 6

Anion

Question 7

What are isotopes?

Answer 7

Atoms of the same element with different number of neutrons

Question 8

How do you calculate the average mass?

Answer 8

Total mass/number of atoms

Question 9

What is a radioisotope?

Answer 9

A nucleus which contains too many or too few neutrons.