Atomic Structure ( AS )

Question 1

what letter is used to represent the atomic number of an atom?

Answer 1

Z

Question 2

what does the atomic number tell us about the element?

Answer 2

number of protons in a atom

Question 3

what letter represents the mass number

Answer 3

A

Question 4

how is the mass number calculated?

Answer 4

number of protons+number of neutrons

Question 5

define relative atomic mass

Answer 5

average mass of all isotopes of an element relative to 1/12th the mass of a Carbon-12 atom

Question 6

what are isotopes?

Answer 6

elements with the same number of protons and electrons but different number of neutrons

Question 7

how many orbitals and electrons do these shells contain(1s,2p,3s,3d,4s)

Answer 7

a)1s-1 orbital, 2 electrons
b)2p-3 orbitals, 6 electrons
c)3s-1 orbital, 2 electrons
d)3d-5 orbital, 10 electrons
e)4s-1 orbital, 2 electron

Question 8

why does the 3d orbital fill before the 4s orbital?

Answer 8

the 3d orbital gets filled before the 4s orbital because its closer to the nucleus and requires less energy to fill up

Question 9

what is a orbital?

Answer 9

area of probability of finding a electron

Question 10

what would be the relationship between 2 electrons in the same orbital?

Answer 10

have opposite spin because they both have a negative charge so they would repel each other

Question 11

explain why chromium does not fit the trend for electron configuration

Answer 11

it only has one electron in its 4s orbital before filling the 3d orbital

Question 12

name one of the ionisation used for mass spectrometery

Answer 12

electron impact: electron gun(hot wire filament with current flowing through it emitting electrons) knocks off one electron from each particle to form 1+ ion

Question 13

describe how a time of flight mass spectrometer works

Answer 13

1)Acceleration- positive ions attracted towards negatively charged plate( ions accelerated to have the same kinetic energy)
2)Ion drift- ions are then deflected by a magnetic field into a curved path. The radius of their path is dependent on the charge and mass of the ion
3)Detection - When the positive ions hit the negatively charged detection plate, they gain an electron, producing a flow of charge. The greater the abundance, the greater the current

Question 14

define first ionisation energy

Answer 14

the amount of energy needed to remove one mole of electron from one mole of gaseous atom to form one mole of gaseous 1+ ion

Question 15

Explain why aluminium doesn’t fit the ionisation energy trend

Answer 15

Aluminium has its outer electron in the p orbital, which is at a higher energy level and is less attracted to the nucleas because it’s further away from it, so less energy is needed to remove that one electron