Atomic Structure

Question 1

What structure is in the centre of an atom?

Answer 1

Nucleus

Question 2

Name the two sub-atomic particles within the nucleus.

Answer 2

Protons and Neutrons

Question 3

What are protons and neutrons collectively known as?

Answer 3

Nucleons

Question 4

What is around the outside of the nucleus?

Answer 4

Electrons

Question 5

What type of charge do each if the three sub-atomic particles have?

Answer 5

Protons - +ve
Nuetrons - nuetral (0)
Electrons - -ve

Question 6

What is the (usually) the overall charge of the atom and why is that?

Answer 6

The overall charge of an atom is usually neutral because there is the same number of electrons as protons.

Question 7

What is the symbol for atomic number?

Answer 7

Z

Question 8

What is the atomic number?

Answer 8

Number of protons

Question 9

What is the symbol for mass number?

Answer 9

A

Question 10

The formula for mass number?

Answer 10

Protons + Neutrons = Mass number (A)

Question 11

What is on top of the chemical symbol and what is on the bottom?

Answer 11

Top - Mass Number (A)
Bottom - Atomic Number (Z)

Question 12

Define Electrons

Answer 12

Electrons are small light particles that orbit the nucleus. They are arranged in shell around the nucleus, with each shell containing a maximum number of electron it can hold.

Question 13

Which shell is always filled first?

Answer 13

The innermost shell is filled first then follows the second inner shell and so on.

Question 14

What are the first four shells referred to as?

Answer 14

1 - K
2- L
3 - M
4 - N

Question 15

What is the outer most shell referred to as?

Answer 15

Valence Shell

Question 16

State the four properties the valence shell determines.

Answer 16

Chemical, Thermal, Optical and Electrical

Question 17

Why is copper a good conductor of heat and electricity?

Answer 17

There is one electron in the valence shell which easily leaves the atoms allowing it to act as a free electron.

Question 18

State the group number of noble gasses.

Answer 18

Group 18

Question 19

Give me three examples of Nobles Gases

Answer 19

Any of the three - Helium, Neon, Argon, Xenon, Krypton, Radon and Ogenessan

Question 20

What noble gas is used for cooling MRI scanners?

Answer 20

Helium

Question 21

What does it mean when noble gases are inert and why are they this way?

Answer 21

Inert means noble gases are less to non - reactive due to their valence shell being full

Question 22

How are electrons held in their shell?

Answer 22

They are held by a binding energy due to the electrical charges of both the electrons and protons.

Question 23

What determines the strength of the binding energy?

Answer 23

The closer the shells is to the nucleus, the stronger its binding energy, e.g. the binding energy of K shells is stronger than L shell

Question 24

What is the unit of measurement of binding energy?

Answer 24

keV (kiloelectronvolt)

Question 25

State the binding energy of a tungsten atom (from K to M) - include their number of electrons.

Answer 25

K - 70 keV - 2
L - 11 keV - 8
M - 2 keV -18

Question 26

What makes an atom electrically stable?

Answer 26

When there is the same amount of electrons and protons, which cancels out allowing them to be stable.

Question 27

What happens when an electron is removed from an atom?

Answer 27

The protons with outnumber the remaining electrons leaving the atom with a net positive charge. This process is called ionisation, and in this case the ionised atom is known as a positive ion.

Question 28

What needs to happen for an electron to be removed from its shell?

Answer 28

The binding energy has to be overcome for an electron to be removed. The more protons in the nucleus the higher the binding energy required to remove an electron , as well as the close the shell to the nucleus, the higher the binding energy.

Question 29

How are x - rays created?

Answer 29

X - rays are created when atoms are ionised by free electrons - the kinematic energy within the free electron transfers to overcome a bound electron’s binding energy.

Question 30

What happens when atoms in the body get ionised?

Answer 30

Atoms in the body can be ionised by x - ray photons, this leads to chemical changes occurring which can cause permanent damage

Question 31

What is an isotope.

Answer 31

An atom that has the same atomic number (Z) but a different mass number (A) - as the number of neutrons can vary.

Question 32

State the two ways isotopes occur.

Answer 32

Naturally or Artificially

Question 33

Give two examples of isotopes

Answer 33

Technetium - 99m (used for nuclear med.)
Cobalt - 60 (used for gamma knife)