CIE A Level Chemistry Solved Past Paper Oct/Nov 2020 P11, 12 & 13

CIE-A-Level-Chemistry-March-2020-P12

CIE A Level Chemistry Solved Past Paper May/June 2020 P11, P12 & P13

1 ai) Barium metal burns with pale green flame and forms white solid BaO.

1c) Gallium has an electron configuration of 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p1: lowest energy level is the one which is nearest to the atom’s nucleus and that is s subshell of quantum shell 1. Highest energy level is in quantum shell 4 and has p subshell with only 1 electron.

1 ai) Subatomic particles of an atom are protons, neutrons & electrons. Isotopes are atoms of same element with same number of protons but different number of neutrons.