A: atomic and electronic structure

subatomic particles

proton

neutron

electron

charge and mass of proton

charge +1

mass 1

charge and mass of electron

charge -1

mass 1/1836

charge and mass of neutron

charge - no charge

mass - 1

atomic number

represents the number of protons in an atom

atomic mass

represents the number of protons and neutrons in an atom

how to get number of protons

atomic number

how to get number of neutrons

atomic mass - atomic number

how to get number of electrons

atomic number

isotopes

when two atoms of the same element have the same number of protons and a different number of neutrons

ions

when an atom gains a charge when it gains or lose an electrons

cation

atom loses an electron and becomes positively charged

anion

atom gains an electro and becomes negatively charged

relative atomic mass

average mass of an atom that is compared to a 1/12 mass of a 1/12 carbon atom

formula for relative atomic mass

(mass x abundance) + (mass x abundance) / total abundance

relative formula

sum of all masses in an atom

groups

vertical columns in the periodic table

periods

horizontal columns in the periodic table

blocks

indication of which subshell contains the highest energy electron

what do electron shells contain

subshells

what do subshells contain

orbitals

orbitals

region of area where there is a 95% chance of finding an electron

how much electrons can an orbital hold

2 electrons

types of subshells

s p d f

how many orbitals and electrons can sub shell s hold

has 1 orbital

has 2 electrons

how many orbitals and electrons can sub shell p hold

holds 3 orbitals

has 6 electrons

how many orbitals and electrons can sub shell d hold

holds 5 orbitals

has 10 electrons

hope many orbitals and electrons can sub shell f hold

holds 7 orbitals

has 14 electrons

types of principles you need to know

aufbau principle

hunds rule

pauli exclusion principle

aufbau principle

electrons fill their orbitals of the lowest energy first

aufbau principle filling order

1s

2s

2p

3s

3p

4s

3d

4p

pauli exclusion principle

orbital contains 2 electrons and those two electrons must have the opposite spins

hunds rule

electrons enter orbitals that have the same sub shell wit the parallel spins before pairing up to minimise the electron to electron repulsion

first ionisation energy

the energy required to remove one mole of electron rom one mole of gaseous atom to form one mole of gaseous +1 ion

second ionisation energy

the energy required to remove one mole of electron from one mole of gaseous +1 iron to form one mole of gaseous 2+ ion

evidence for hell structure rom successive ionisation energies

• ionisation energy increases and the remaining electrons experience less repulsion and greater net nuclear attraction per electron

• large jumps of ionisation occur when an electron is removed from anew shell closer to the nucleus

factors affeting ionisation energy and trends

nuclear

• more protons have a stronger electrostatic attraction between the nuclear and the higher electrons (higher ionisation)

atomic radius/distance

• further outer electrons form the nucleus will result its weaker electrostatic attraction (lower ionisation)

shielding

• inner filled shells blocked/shield the outer electrons from the full pull of the positive nucleus will lead to a lower ionisation

trends across a period when going down a group

• number of shells increase → atomic radius increases → shielding increases

• the outer electron is further from the nucleus and less strongly held making it easier to lose

trends across a group when going down a group

• proton number increase → nuclear charge increase

• electrons have the same number of shells so holding roughly stays the same

• atom radius decreases slightly meaning more electrons are closer to the nucleus meaning a stronger nuclear attraction.

about the trends on the periods, what periods are an anomaly to this trend

group 2

group 3

group 5

group 6

group 2 and group 3 anomalies

• magnesium, —> Aluminium

• aluminiums outer shell is in the 3p sub shell which is slightly higher energy level and shielded by the 3s sub shell making it more easier to remove more thane magnesiums 3s electron

group 5 and group 6 anomalies

• nitrogen → oxygen or phosphorous → sulfur

• oxygen has paired electrons with one of its 2p orbitals (2p⁴). Electron to electron repulsion in the paired orbital makes the electron more easier to remove more than nitrogens half filled 2p³ sub shell

electron to electron repulsion

electrostatic force that pushes negatively charged electrons away from each other.