Periodicity + TM

What does the block (ex s-block) tell us

In which sub-level the highest energy valence electrons are found

Define electron shielding

When outer electrons are shielded from the attraction of the nucleus by inner electrons due to the presence of electrons in lower energy levels

Define the first ionization energy

the energy required to remove one mole of electrons from each atom in one mole of gaseous atoms under standard conditions

State the trend of ionisation energy across and down the period/group + why

across the period it increases due to an increase in nuclear charge, down the period in decreases due to the distance between valence electron and nucleus increasing

Define electronegativity

the attraction of an atom for a bonding pair of electrons (towards itself) of the covalent bond it is a part of

State the vertical and horizontal trends for electronegativity

vertical - decreases down the group, size of atoms increase. horizontal - increases due to an increae in nuclear charge

Define electron affinity

the energy released when one mole of electrons are added to one mole of gaseous atom under standard conditions

State the vertical and horizontal trends for electron affinity

vertical - decrease as the distance between nucleus and velence shell increases (less attraction) horizontal - increase due to the increases in nuclear charge - more attraction

What is the trend of melting point across a period

Increase to giant covalent (middle) then decrease to simple covalent (metal higher than simple covalent tho)

What is produced when an alkali metal reacts with water?

metal hydroxide (salt) and hydrogen

Define amphoteric

A substance which has acidic and basic properties

Define a transition element

an element that forms at least one stable ion with a partially filled d subshell

Why is Zinc not an transition element?

Because it doesn't form an ion with partially filled d subshells - the 2+ ion has full d subshells

State 5 properties of transition metals

Have multiple oxidation numbers, form complex ions, form coloured compounds, good catalysts, magnetic properties

When ionizing, are 3d or 4s electrons removed first?

4s

Which oxidation number do all transition metals have and why?

2+ mostly due to losing the 4s electrons

Why do transition elements have multiple oxidation states?

Because the 4s and 3d subshells are close in energy, there are no big jumps in ionisation energies

Define a ligand

negative ions or neutral molecules that have lone pairs of electrons - use lone pairs to bond to a metal ion to form complex ions

Define a dative / coordiante covalent bond

A covalent bond in which both electrons come from the same atom

What kind of reaction do complex ions undergo?

substitution - ligands are replaced

What is the coordinate number

The number of coordinate covalent bonds formed between ligand and central metal ion

Is a ligand a lewis base or acid?

Lewis base - give an electron

How does a solution of complex ions get its colour

the 5 d orbitals split (2 high and 3 lower) due to the repulsion between electrons on the metal and the lone paris on the ligands, then if a certain frequency of light hits an electron in the lower d orbitals it is promoted to the higher d-orbitals so it absorbs that light - then all the other colours are reflected and the complementary colour of the colour that was absorbed is seen

What do the formation of coloured substances require?

a partially filled d subshell

Which two transition metals do not form coloured compounds

Cu+ and Sc3+ - d orbitals either completely full or empty

What affects the colour of the metal compounds? (3)

the 5d orbital splitting - greater distance, higher frequency needed for promotion, 1. identity of the metal - different electron arrangment - 2. oxidation number if metal and ligands are the same - the greater the oxidation number, the greater the splitting - 3. nature of ligand - spectrochemical series, indicate how much splits