Topic 1 - atomic structure and the periodic table

what is the mass number

protons +neutrons

What term tells you how many protons an atom has

atomic number

what does the x-axis on mass spectrometry show

the m/z value

what does m/z mean

mass over charge

what does the y-axis on mass spectrometry show

relative abundance of each ion

how do you find the relative molecular mass from the mass spec

the highest peak is equal to the relative molecular mass

what do short lines after the relative molecular mass mean on mass spec

isotopes

what is an element

substance made from only one type of atom

what is an isotope

atom with the same number of protons but a different number of neutrons

why do isotopes have the same chemical properties as regular ions

they have the same electron configuration

what is the relative isotopic mass

mass of an atom of an isotope compared to 1/12th of the mass of a carbon-12 atom

what is relative atomic mass

average mass of an atom of an element compared to 1/12th the mass of a carbon-12 atom

what is the first ionisation energy

amount of energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions

what three factors affect ionisation energy

nuclear charge, atomic radius, shielding

how does nuclear charge affect ionisation energy

more protons means there is a stronger positive charge so stronger electrostatic attraction

how does atomic radius affect ionisation energy

as electrons are further away from the nucleus there is weaker electrostatic attraction

how does shielding affect ionisation energy

if outer electrons are highly shielded then they don’t experience as much nuclear charge

how and why does ionisation energy change down a group

decreases because nuclear charge, atomic radius and shielding all increase

how and why does ionisation energy change across a period

it will generally increase as nuclear charge increases, atomic radius decreases and shielding stays similar

what happens with successive ionisation energy’s

ionisation energy will increase with each new shell being taken from. Electrostatic attraction increases as electrons are removed

what shape is an s-orbital

spherical

what shape is a p-orbital

dumbbell

how is the modern periodic table organised

by atomic number

what is the general pattern for melting and boiling points across a period

increases for giant structures then decreases for simple molecules

why does melting and boiling point increase for giant structures

metallic bonding increases across a period and other structures have strong bonds from their giant covalent lattice structures

why does the strength of metallic bonds increase across a period

the ions have a larger positive charge, smaller ionic radius, more delocalised electrons and therefore stronger electrostatic attraction

why do simple molecules have low melting and boiling points

only have weak induced dipole0sipole forces between the molecules

how does atomic radius change across a period

decreases

why does atomic radius decrease across a period

nuclear charge increases, no shielding for inner electrons, stronger electrosatic attraction