1.1 Atomic Structure

Question 1

Who invented the “Plum pudding model”?

Answer 1

J.J Thompson (1897)

Question 2

Who discovered the electron?

Answer 2

Ernest Rutherford (1911)

Question 3

Who discovered the neutron and why was it last to be discovered?

Answer 3

James Chadwick (1932) ; because it has no charge so it was harder to discover.

Question 4

What is the definition of “mass number”?

Answer 4

The number of protons and neutrons in the nucleus of an atom

Question 5

What is the definition of “atomic number”?

Answer 5

The number of protons in the nucleus of an atom

Question 6

What is the relative atomic mass and charge of a neutron?

Answer 6

1 and 0

Question 7

What is the relative atomic mass and charge of a proton?

Answer 7

1 and 1+

Question 8

What is the relative atomic mass and charge of a electron?

Answer 8

1/1840 and 1-

Question 9

What is the definition of an isotope?

Answer 9

Isotopes are atoms, of an element, which have the same atomic number (number of protons) but different mass number (number of protons and neutrons)

Therefore they have different numbers of neutrons in their nucleus.

Question 10

Describe the ‘plum pudding model’

Answer 10

A positive matrix (cake) with negative electrons (plums) embedded in it.

Question 11

Describe the rules of how electrons are configured when drawings outer orbits of electrons

Answer 11

-1st shell: up to 2 electrons
-2nd shell: up to 8 electrons
-3rd shell: up to 8 electrons
-4th shell can be started

Question 12

Describe the structure of an atom

Answer 12

A central positively charged nucleus containing protons and neutrons surrounded by orbiting electrons in shells

Question 13

Why do atoms have no charge?

Answer 13

They have an equal number of positively charged protons and negatively charged electrons which cancel out each others charge

Question 14

What is the size of a nanometre, picometre and femtometre in metres?

Answer 14

Nanometre- 1x10-9m

Picometre- 1x10-12m

Femtometre- 1x10-15m

-the typical atomic radius is 1x10-10m and the typical radius of a nucleus is 1x10-14m (10,000 times smaller than the atomic radius)

Question 15

What is the definition of an ion, element and compound?

Answer 15

Ion- an electrically charged particle formed when an atom when it gains or loses an electron or electrons.

Element- a single pure substance that cannot be broken down into anything simpler by chemical means.

Compound- a single pure substance made from two or more elements chemically combined.