accept calcium has a 2+ charge / calcium ion has a 2+ charge allow Ca2+ chlorine atoms gain electrons • accept chloride ion formed gain one electron • accept chlorine / chloride has a negative charge / is a negative ion/ is a negative particle allow Cl– if no other marks awarded allow ionic bonding or complete outer shell for 1 mark 4 [8] Q37. (a) any one from: they are negative / anions • allow Cl– ignore atoms / chlorine do not accept chloride ions are negative electrodes they are attracted • they are oppositely charged • 1 (b) hydrogen is less reactive than sodium 1 (c) hydroxide (ions) / OH– ignore OH do not accept NaOH / sodium hydroxide 1 (d) (i) allow any combination of dots or crosses
accept calcium has a 2+ charge / calcium ion has a 2+ charge allow Ca2+ • chlorine atoms gain electrons accept chloride ion formed • gain one electron accept chlorine / chloride has a negative charge / is a negative ion/ is a negative particle allow Cl– if no other marks awarded allow ionic bonding or complete outer shell for 1 mark 4 [8] Q37. (a) any one from: • they are negative / anions allow Cl– ignore atoms / chlorine do not accept chloride ions are negative electrodes • they are attracted • they are oppositely charged 1 (b) hydrogen is less reactive than sodium 1 (c) hydroxide (ions) / OH– ignore OH do not accept NaOH / sodium hydroxide 1 (d) (i) allow any combination of dots or crosses
chemical_changes_part_2_mark_schemes.docx