Periodicity

Question 1

What is the trend atomic radii across the period?

Answer 1

Across the period atomic radius decreases
Nuclear charge increases
Shielding remains constant leading to an increase in attraction between the outermost energy level of electrons and nucleus

Question 2

What is a trend in atomic radii down a group?

Answer 2

Down a group atomic radius increases
Nuclear charge increases(but this isn’t significant)
Shielding increases since number of shells increase
Leading to a decrease in attraction between the Optimus energy level of electrons on the nucleus

Question 3

How does the melting point change from sodium to aluminium?

Answer 3

Increase in melting point
Increase from sodium to aluminium because ions get smaller and more positive more delocalised electrons so stronger electrostatic attraction between the positive ions and delocalised electrons so require more energy to break

Question 4

How does a melting point change across period three from Silicon to Argon?

Answer 4

Macro molecular structure each silicon atom is attrachedto four others . Many strong covalent bonds between these atoms so a large amount of energy is required to break these bonds.
Phosphorus sulphur, chlorine: simple molecular – only weak Vandals forces of attraction between molecules strength is in order as a molecules decrease in size so energy requires to break these forces decreases in the same order hence the observed trend

Question 5

Which molecules are macromolecular?

Answer 5

Giant covalent (diamond, graphite, graphing, silicon dioxide

Question 6

Describe argon

Answer 6

Is this a single atom to the early forces between them are very weak van der vaals bonds

Question 7

What elements are giant metallic in period two period three and what is the attraction between the particles?

Answer 7

Lithium beryllium boron
Sodium magnesium aluminium

Strong electrostatic attraction between metal ions and delocalised electrons

Question 8

What elements in period two and three are giant covalent and what is the attraction between the particles?

Answer 8

Carbon and silicon

Strong available bonds between atoms

Question 9

What elements in period two and period three are simple molecular and what is the attraction between particles?

Answer 9

Nitrogen oxygen, fluorine, neon
Phosphorus, sulphur, chlorine, argon

Weak molecular forces between molecules