Inorganic - Periodicity

Question 1

what do all elements along a period have in common?

Answer 1

the same number of electron shells

Question 2

what do all elements down a group have in common?

Answer 2

same number of outer electrons

Question 3

which groups are in the s-block?

Answer 3

groups 1 and 2

Question 4

which groups are in the p-block?

Answer 4

groups 3 to noble gases (8/0)

Question 5

which elements are in the d-block?

Answer 5

transition metals

Question 6

which elements are in the f-block?

Answer 6

radioactive elements

Question 7

what is the trend in atomic radius along a period?

Answer 7

decreases

Question 8

why does atomic radius decrease along a period?

Answer 8

• increased nuclear charge means the outer electrons are pulled in closer to the nucleus
• increased charge produces a greater electrostatic attraction, therefore atomic radius is decreased

Question 9

what is the trend in atomic radius down a group?

Answer 9

increases

Question 10

why does atomic radius increase down a group?

Answer 10

• an electron shell is added each time
• increasing the distance between the outer electrons and nucleus and the shielding
• therefore reducing the strength of the electrostatic force and so atomic radius increases

Question 11

what is the trend in ionisation energy along a period?

Answer 11

increases

Question 12

why does ionisation energy increase along a period?

Answer 12

• decreasing atomic radius and increasing nuclear charge
• so the strength of the electrostatic force is increased
• therefore more energy is required to remove the outer electron

Question 13

what is the trend in ionisation energy down a group?

Answer 13

decreases

Question 14

why does ionisation energy decrease down a group?

Answer 14

• electrostatic attraction between the nucleus and outer electrons decreases and shielding increases
• therefore less energy is required to remove the outer electron

Question 15

what kind of bonding do sodium, magnesium, and aluminium have?

Answer 15

metallic

Question 16

why do the melting points from sodium to magnesium to aluminium increase?

Answer 16

• each has a greater positive charged ion and more electrons released to the sea of delocalised electrons
• so the electrostatic forces increase from Na to Al
• therefore requiring more energy to overcome

Question 17

what kind of structure does silicon have?

Answer 17

giant covalent structure

Question 18

why does silicon have a very high melting point?

Answer 18

• the silicon atoms are held by strong covalent bonds in a tetrahedral structure
• these bonds require a lot of energy to overcome, giving it a high melting point

Question 19

what kind of structural molecules are phosphorous, sulphur, and chlorine?

Answer 19

simple covalent molecules held with weak Van der Waals forces

Question 20

why do phosphorous, sulphur, and chlorine have low, similar melting points?

Answer 20

they are held together by weak Van der Waals forces which only require a little energy to overcome