Atomic Structure

Question 1

Calculating RAM

%

Answer 1

(% x mass) + (% x mass) / Total %

Question 2

Calculating RAM

ratio

Answer 2

(Number x mass) + (number x mass) / total number

Question 3

Define RAM

Answer 3

the average mass of 1 mole of an element relative to 1/12th of 1 mole of Carbon 12

Question 4

RAM stands for

Answer 4

Relative Atomic Mass

Question 5

Define Atomic Number

Answer 5

the number of protons in the nucleus of an atom

Question 6

Define Mass Number

Answer 6

the total number of protons and neutrons in the nucleus

Question 7

Give the Relative Mass and relative charge of a proton

Answer 7

RM 1

RC +1

Question 8

Give the Relative Mass and relative charge of an electron

Answer 8

RM 1/1836

RC-1

Question 9

Give the Relative Mass and relative charge of a neutron

Answer 9

RM 1

RC 0

Question 10

Define isotope

Answer 10

atoms of the same element which have the same number of protons but different number of neutrons

Question 11

What happens in the ‘Ionisation’ stage? (Mass Spec)

Answer 11

• sample injected via sample inlet in gas form
• electron ‘gun’ bombards atoms with electrons to ‘knock’ an electron out of the atom
• atoms become negative ions
• there is a vacuum so the sample doesn’t get contaminated

Question 12

What is the equation for Ionisation? (mass spec)

Answer 12

x (g) –> x+ + e-
OR
x (g) + e- –> x+ + 2e-

(x is any element, noble gases included)

Question 13

What happens in the ‘Acceleration’ stage? (Mass Spec)

Answer 13

-ions accelerated by electromagnetic field
-all have the same kinetic energy NOT speed
(speed is inversely proportional to mass)

Question 14

speed is ……………. proportional to mass

Answer 14

inversely

Question 15

What happens in the ‘Drift’ stage? (Mass Spec)

Answer 15

• same kinetic energy
• the heavier the ion the slower it travels and vice versa
• this separates different ions

Question 16

What happens in the ‘Detection’ stage? (Mass Spec)

Answer 16

• detector measures electrical current
• movement of e- is the current
• e- move towards the +ive atoms

Question 17

current is …………… proportional to the amount of ions

Answer 17

directly

Question 18

current (mass spec)

Answer 18

• current = the graph

- current is directly proportional to the amount of ions

Question 19

mass spec graph

Answer 19

• x axis = mass /charge

- can also measure time

Question 20

11Na 
1s2, 2s2, 2p6, 3s1
17Cl
1s2, 2s2, 2p6, 3s2, 3p5
Which needs a higher Ionisation Energy? Why?

Answer 20

Cl:

• more protons
  
  • has a larger molecular charge
• atom is getting smaller
  - stronger force of attraction