Electron Theory

Question 1

A neutron has

Answer 1

no electrical charge but will add weight to the nucleus.

Question 2

The unit which consists of two or more different types of atoms is known as a

Answer 2

molecule of a compound.

Question 3

In what equipment is a photon radiated when an electron leaves a hole?

Answer 3

LED.

Question 4

A good electrical insulating material will contain

Answer 4

strongly bound electrons in the atoms of the material.

Question 5

The smallest particle that a substance can be split and show the same properties as the whole is known as

Answer 5

an Atom.

Question 6

What charge does the nucleus of an atom possess?

Answer 6

Positive.

Question 7

What is the maximum number of electrons in shell N of an atom?

Answer 7

32.

Shell k = 2 electrons, shell L= 8 electrons, shell M = 18 electrons and shell N = 32 electrons (or use the 2n2 exclusion rule).

Question 8

An oxygen molecule is made up of

Answer 8

two oxygen atoms sharing electrons.

Question 9

If electrons are added to an atom it becomes

Answer 9

a negative ion.

Question 10

An element whose atoms have fewer than 4 electrons in their valency shell are

Answer 10

good conductors.

The further away from a ‘complete’ shell the better a conductor it is.

Question 11

The charge on a proton is

Answer 11

positive.

Question 12

What effect do the electrons of one atom have upon the electrons of another atom?

Answer 12

They repel each other.

Question 13

What is a molecule?

Answer 13

The smallest part of a compound.

Question 14

An atom is

Answer 14

the smallest part of an element that retains its characteristics.

Question 15

A neutron is a particle which is

Answer 15

contained within the nucleus of most atoms.

Most atoms’ because hydrogen has no neutron.

Question 16

The mass of an atom is contained mainly in the

Answer 16

nucleus.

The proton and the neutron are approximately the same mass (neutron very slightly heavier). The electron is just under 1/2000th of a proton or neutron.

Question 17

When an atom loses or gains an electron it is called

Answer 17

an ion.

Question 18

A good electrical insulator is a material which

Answer 18

has its electrons tightly bound to their parent atoms.

Question 19

An electric current is

Answer 19

an ordered flow of electrons.

Question 20

An atom contains

Answer 20

Protons neutrons & electrons.

Question 21

Germanium and silicon have how many electrons in their outer shell?

Answer 21

4.

All semiconductors (including carbon) has 4 electrons in their outer shell.

Question 22

If a free electron is given to another atom, that atom is a

Answer 22

negative ion.

That atom will be negatively charged due to the additional electron.

Question 23

The atomic number of an atom is determined by the number of

Answer 23

protons.

Atomic number = number of protons. Mass number = number of protons + neutrons.

Question 24

The valence electron is

Answer 24

the electron in outer shell of atom.

Question 25

An atom with a deficiency in electrons has

Answer 25

low resistance.

An atom with a deficiency of electrons will be positively charged and able to accept electrons freely. Module 4 theory of holes as majority carriers.

Question 26

An atom with less than 4 electrons in its outer shell has

Answer 26

low electrical resistance.

Low electrical resistance, i.e. a good conductor.

Question 27

Elements such as phosphorus with 5 electrons in their outer shell, when combined with pure silicon, is a

Answer 27

donor.

Phosphorus ‘donates’ an electron to the silicon crystal structure.

Question 28

A hydrogen atom consist of a

Answer 28

Proton and an Electron only.

Hydrogen has no Neutron.

Question 29

For an atom to become a negative ion it must

Answer 29

gain at least one electron.

Gaining at least one electron produces a negative ion.

Question 30

What is the maximum number of electrons in shell M of an atom?

Answer 30

18.

Use Pauli’s exclusion formula. M is the 3rd shell (n=3). 233 = 18.

Question 31

A neutral atom with an atomic no. of 3 has how many electrons?

Answer 31

3.

Atomic number = number of protons = number of electrons.

Question 32

The nucleus of an atom is

Answer 32

positive charged.

Question 33

Electron orbits are called

Answer 33

shells.

shells, or energy levels.

Question 34

What happens when a neutral atom gains electrons.

Answer 34

It gains a negative charge.

Question 35

An oxygen atom has

Answer 35

protons, neutrons and electrons.

Question 36

What are the names of the shells on an Atom

Answer 36

K, L, M, N, O, P, and Q, or 1, 2, 3, 4, 5, 6, and 7. The K shell is the innermost shell, and the Q shell is the outermost shell