Chap 4: Molecules and Compounds.

Question 1

Which transition metals form only one kind of stable ions

Answer 1

Zinc, Silver, and Scandium

Question 2

What are molecular compounds.

Answer 2

Compounds composed of two or more non-metals.

Question 3

Naming of binary molecule compounds

Answer 3

• Your write the element with the smallest group number first.
• if same group, write the one with the greatest row number fiirst.
• If there’s only one atom of the first element, then the prefix “mono” is omitted. (rem: not for the second atom)
  ex: Nitrogen dioxide, but for second atom (dinitrogen monoxide)

Question 4

types of acids

Answer 4

• Binary acids: Composed of hydrogen and one (or a group of) non-metal. (ex: HCl). In gas phase, they behave as covalent compounds, but when dissolved in water, they behave as acids.
• Oxyacids: contain one or more hydrogen ions and an oxyanion(ex: Nitric acid, Sulphuric acid, and so on). (Chromate becomes Chromic acid)
• Organic acids: Formate ion - Formic acid (methanoic acid), and acetate ion - Acetic acid (ethanoic acid).

Question 5

Allotropes of carbon

Answer 5

Graphite; Hexagonal arrangment of carbon atoms
Diamond: cubic crystalline arrangement.
fullerenes: Hollow spheres arrangement.

Note: two carbon atoms form cabide anions which forms compounds with transition metals.

Question 6

Hydrocarbons and different btn saturated and unsatureated hydrocarbons

Answer 6

Compounds containing only hydrogen and carbon only
saturated: Contain only single bonds

unsaturated: they contain double or triple bonds.

Question 7

Ethylene and Acetylene.

Answer 7

Ethylene is Ethene (alkene) and acetylene is ethyne (alkyne).

Question 8

Isoelectronic

Answer 8

• Having the same number of electrons or electronic structure.

Question 9

Is the formation of ionic bonds endothermic or exothermic.

Answer 9

• It is usually exothermic: it gives out heat.

Question 10

the bonding in hydronium and ammonium.

Answer 10

• These polyatomic ions have covalent bonds within them.

Question 11

What are Oxyanions ?

Answer 11

Oxygen in combination with another element forms anion.

Question 12

What are ligands ? and what’s the name when it’s water

Answer 12

A group of neutral molecules or ions that coordinate to a metal ion. (forex; water in Copper (II) Sulphate pentahydrate.

Note: when the ligand is water, the corresponding complexes are called hydrated complexes.

Question 13

Difference btn electronegativity and electron affinity.

Answer 13

Electronegativity is the ability of an electron to attract electrons towards itself while electron affinity is the indication that the atom prefers to hold onto an extra electron.

Question 14

Highest and lowest electronegative elements

Answer 14

F and Francium.

Note: noble gases are not assigned electronegativity values.