2.1 Periodicity Flashcards
How are elements in the periodic table arranged
Their proton number
What does the group number indicate on the periodic table
The number of outer electrons of an element
What elements are in each block of the periodic table
s-block = groups 1 and 2
p-block = groups 3 to 0
d-block = transition metals
f-block = radioactive elements
What is periodicity
The study of trends within the periodic table often linked to elements’ electronic configuration
What is the trend in atomic radius along a period
Atomic radius decreases
Why does atomic radius decrease along a period
Due to an increased nuclear charge for the same number of electron shells
The outer electrons are pulled in closer to the nucleus because the charge produces a greater attraction
What is the trend in atomic radius going down a group
Atomic radius increases
Why does atomic radius increases going down a group
More electron shells, larger distance between outer electrons and nucleus reducing power of attraction
More electron shielding, nuclear attraction is reduced
What is the trend in ionisation energy along a period
Ionisation energy increases
Why does ionisation energy increase along a period
Because atomic radius decreases and nuclear charge increases
Outer electrons are held more strongly so more energy is required to remove the outer electron and ionise the atom
Trend in ionisation energy going down a group
Ionisation energy decreases
Why does ionisation energy decrease down a group
Nuclear attraction between nucleus and outer electrons reduces and shielding increases
Less energy is required to remove outer electron
What does mtp of period 3 elements depend on
Structure of element
Bond strength
What happens to mtp across period 3 between sodium and aluminium
All have metallic bonds, mtp increase due to greater positive charge
More electrons releases
More electrostatic forces so more energy is needed to break them
Why does mtp increase dramatically for silicone in period 3
Very strong covalent structure
More energy required to break strong covalent bonds