Atomic structure

Question 1

Subatomic particles

Answer 1

Protons (+ve) mass 1
Neutrons (neutral) mass 1
electrons (-ve) mass: negligible

Question 2

Isotopes

Answer 2

A variant atom from the same element with the same no.of protons and electrons but different no.of neutrons

Question 3

Atomic model

Answer 3

An atom consists of a nucleus and PQS
nucleus consists of subatomic particles protons and neutrons and is positively charged
PQS contains s,p,d,f subshells which consist of orbitals which contain electrons

Question 4

Energy level of orbitals in same subshell

Answer 4

degenerate. Have same energy level

Question 5

Orbital

Answer 5

(each orbital holds a max of 2 electrons)
s- 1 orbital
p-3 orbitals
d-5 orbitals
f-7 orbitals

A region of space where there is a high probability of finding electrons
its shape depends on the energy of electrons
when electron is in an orbital of higher energy level there is a greater possibility that electrons will be found further away from the nucleus

Question 6

Electrons

Answer 6

Do not orbit around the nucleus
move around the nucleus in electronic shells of fixed energy level (PQS)
PQN- n- no.of of PQS

Question 7

Effect of an electric field on protons electrons and neutrons

Answer 7

protons are deflected downwards towards -ve field
electrons deflected upwards towards +ve field
neutrons are neutral and travel in a straight line
charged particles are deflected

Question 8

Factors affecting extent of deflection

Answer 8

1. Charge of particle
2. Mass of particle

greater the charge greater the deflection
greater the mass lesser the deflection

Angle of deflection ∝ change/mass
formula to find deflection
Θ= k(charge/mass)

Question 9

Relative energy of orbitals

Answer 9

depends on which subshell they are in
s more than p more than d more than f

due to shapes of spdf orbitals electrons in s have greater possibility of being found closer to nucleus hence lower energy level than p and so on

Question 10

Relative energy overlap

Answer 10

As n increases the energy levels

come closer to one another and overlapping of subshells of different PQS occurs

Question 11

Why 4s subshell has a lower energy level than 3d subshell

Answer 11

As n increases energy levels come closer to each other and overlapping of subshells from different PQS occurs

Question 12

Ionisation energy

Answer 12

First ionisation: The energy absorbed in removing one mole of most loosely held electron from one mole gaseous atom to form one mole of singly positively charged gaseous cation
second ionisation: The energy absorbed in removing one mole of most loosely held electron from one mole singly charged gaseous cation to form one mole of doubly positively charged gaseous cation

Question 13

Successive I.E always increases

Answer 13

Due to increasing amount of energy required to remove one mole of most loosely held electrons from an increasingly positive ion (due to removal of electron from more inner shell closer to nucleus)

can be used to determine an element’s group no.

a small jump in S.I.E plot means the electron is being removed from a more inner PQS of lower energy level

a big jump means the electron is being removed from the innermost PQS. which means the electron which was removed before it was from the valence PQS

Question 14

Ground state and Excited state

Answer 14

Ground state: When all electrons occupy lowest energy levels
excited state: When electrons receive energy and are promoted to a higher energy level, the species becomes unstable and is excited

Question 15

Rules

Answer 15

1. electrons occupy an orbital in opposite spins so there is no inter electron repulsion
2. electrons first occupy orbitals singly before doubly. Electrons that occupy an orbital singly are more harder to remove
3. an orbital occupies a max of 2 electrons
4. 4s subshell filled first before 3d unless Cu/Cr
   as atoms’ electronic configuration is more stable that way