(a)(i) Isotopy
(ii) They have different mass numbers or number of neutrons.
(iii) —Hydrogen, —Chlorine. —Carbon, —Oxygen.
(iv) 1 S\(^2\)2S\(^2\)2P\(^62\)3S\(^2\)3P\(^5\)
(b)(i) 1. DIFFERENCES IN PHYSICAL PROPERTIES
METALS | NON — METALS |
Good conductors of heat and electricity | Poor conductors of heat and electricity |
Malleable - can be beaten into thin sheets | Not malleable / brittle |
Ductile — can be stretched into wire | Non ductile / biittle |
Possess metallic luster | Do not possess metallic luster |
Are sonorous | Not sonorous |
Solid at room temperature except mercury / high melting point | Solids, liquids or gases at room temperature / low melting point |
2. DIFFERENCES IN CHEMICAL PROPERTIES
METALS NON | METALS |
Lose their valence electrons easily / ionize by electron loss | Gain or share valence electrons easily / ionize by electron gain |
Form oxides that are basic / amphoteric | Form oxides that are acidic / neutral |
Are good reducing agents | Are good oxidizing agents |
Have lower electro negativities | Have higher electro negativities |
Have low ionization energy | Have high ionization energy |
(Some reactive metals) react with dilute acids to give off hydrogen | Do not react with dilute acids to give off hydrogen. |
(ii) (l) BeO, Al\(_2\)O\(_3\), ZnO, SnO\(_2\), PbO, PbO\(_2\)
(II) LiH, NaH, KH, CaCO\(_3\) MgH\(_2\)
(III) Li\(_2\)CO\(_3\), BeCO\(_3\), MgCO\(_3\), CaCO\(_3\), ZnCO\(_3\), PbCO\(_3\)
(IV) AlCl\(_3\), MgCl\(_2\), PCl\(_3\), SiCl\(_4\), NH\(_4\)Cl
(c)(i) - form coloured compounds / ions, - exhibit variable oxidation states. - form complex compounds / ion. - have magnetic properties (paramagnetism). - have catalytic properties.
(ii) —> 1s\(^2\)2s\(^2\)2p\(^6\)3s\(^2\)3p\(^6\)3d\(^{10}\)4s\(^2\) are fully filled
(d) Mr(MgCO\(_3\)) = 24 + 12 + (16 x 3) 84
Mr(Na\(_2\)CO\(_3\)) = (23 x 2) +12 + (3 x 16) = 106
moles of MgCO\(_3\) = \(\frac{3.36}{84}\) = 0.04
moles of Na\(_2\)CO\(_3\) = moles of MgCO\(_3\) = 0.04
mass of NaCO\(_3\) = 0.04 x106 = 4.24g
OR
Mr(MgCO\(_3\)) = 24 + 12 + (1 6 x 3) 84
Mr(Na\(_2\)CO\(_3\)) = (23 x 2) +12 + (3 x 16) = 106
84g of MgCO\(_3\) produced from 10\(^6\)g Na\(_2\)CO\(_3\)
3.36g of MgCO\(_3\) will be produced
From 106 x \(\frac{3.36}{84}\) = 4.24g