Week 2

Question 1

Melting

Answer 1

Solid to liquid

Question 2

Freezing

Answer 2

Liquid to solid

Question 3

Boiling/vaporising

Answer 3

Liquid to gas

Question 4

Condensation

Answer 4

Gas to liquid

Question 5

Sublimation

Answer 5

Solid to gas

Question 6

Melting and billing points

Answer 6

Solid: mp-positive, bp- positive
Liquid: mp- negative, bp- positive
Gas: mp- negative, bp- negative

Question 7

Electron configuration

Answer 7

Arrangement of the electrons around the nucleus

Question 8

Shells

Answer 8

Electrons moved around the nucleus of an atom in specific energy levels

Question 9

Ground state

Answer 9

When the electron is in the lowest possible energy shell

Question 10

Transition

Answer 10

An electron could move from a lower energy level to a higher energy level by absorbing energy

Question 11

State table

Answer 11

Solid: mp- positive
Bp- positive
Liquid: mp- negative
Bp- positive
Gas:mp- negative
Be-negative

Question 12

Excited state

Answer 12

High energy electron

Question 13

Neils Bohr- the shell model

Answer 13

The visible hydrogen spectrum consists of four lines-red, green, blue and violet- observed by passing an electric current through hydrogen gas.
The electron will transition from its ground state to a higher state by absorbing energy.
The electron in the excited stage is unstable and so it falls back to the ground state and emits the absorbed energy. This energy corresponds to the coloured lines on the spectrum.

Question 14

Shells

Answer 14

The major energy levels in which electrons are located
Shells are numbered 1,2,3 outwards from the nucleus in order of increasing energy
An electron that is close to the nucleus will be attracted more strongly to the nucleus than one that is further away.

Question 15

Electrons in the same shell…

Answer 15

Are about the same distance from the nucleus (shell is circular)
Have about the same energy level (when the electron moves on the shell, no spectrum is observed)

Question 16

The further an electron is from the nucleus…

Answer 16

The smaller the amount of energy required to remove it from the atom (because weaker electrostatic attraction)

Question 17

Different shells

Answer 17

Hold different numbers of electrons

Question 18

The octate rule

Answer 18

The outermost shell can never contain more than eight electrons regardless of the maximum possible number for that shell.

Question 19

Shell no. To max. no. Electrons

Answer 19

2n^2

Question 20

Valence electrons

Answer 20

The electrons in the outermost shell of an atom are called valence electrons and are involved in chemical reactions because they are unstable.

Question 21

Sub-shells

Answer 21

Found within shells
The number of sub shells in each shell is equal to its shell number(shell 3 has 3 sub shells.)
Given the labels s,p,d,f
Have energies within each shell in the order s<p></p>

Question 22

Pauli principle

Answer 22

Gives the number of electrons in any orbital

An atomic orbital can hold a maximum of two electrons.

Question 23

Pauli principle table

Answer 23

Sub shell. No. Of orbitals. Max no of electrons
S. 1. 2
P. 3. 6
D. 5. 10
F. 7. 14

Question 24

The order of filling the shells and sub shells

Answer 24

Electrons occupy the lowest energy sub shell in an atom first
As shells move away from the nucleus they get closer to each other. In some cases the sub shells of one shell are higher in energy than sub shells of the next shell (4s and 3D)

Question 25

Sub shell energy formula

Answer 25

if n>_ 3; E(n+1)s