NonmetalsNonmetals

Ashton LokarAshton Lokar

AP ChemAP Chem

The Nonmetals are:The Nonmetals are:

Hydrogen (H)Hydrogen (H)

Helium(He)Helium(He) Carbon (C) Carbon (C) Nitrogen (N) Nitrogen (N) Oxygen (O)Oxygen (O) Fluorine (F) Fluorine (F) Neon(Ne)Neon(Ne) Phosphorus (P)Phosphorus (P)

Sulfur (S) Sulfur (S) Chlorine (Cl)Chlorine (Cl) Argon (Ar)Argon (Ar) Selenium (Se)Selenium (Se) Bromine (Br)Bromine (Br) Krypton (Kr)Krypton (Kr) Iodine (I)Iodine (I) Xenon (Xe)Xenon (Xe) Radon (Rn)Radon (Rn)

Reactivity of NonmentalsReactivity of Nonmentals

Nitrogen is least reactive due to Nitrogen is least reactive due to triple bonds that hold the N2 triple bonds that hold the N2 molecule together molecule together

A large exothermic reaction occurs A large exothermic reaction occurs giving off hundreds of kilojoules of giving off hundreds of kilojoules of energy when the N2 molecule is energy when the N2 molecule is broken, this is why explosives broken, this is why explosives commonly contain nitrogencommonly contain nitrogen

Reactivity of Nonmetals Reactivity of Nonmetals (cont.)(cont.)

Fluorine is the most reactive element Fluorine is the most reactive element because of the weakness of the single because of the weakness of the single bond in the F2 moleculebond in the F2 molecule

It has an E * red of +2.889 VIt has an E * red of +2.889 V It bonds with all elements except for He, It bonds with all elements except for He,

Ne and ArNe and Ar It even bonds with water which means It even bonds with water which means

reactions of compounds containing reactions of compounds containing fluorine reacting with water cannot occurfluorine reacting with water cannot occur

Reactivity of Nonmetals Reactivity of Nonmetals (cont.)(cont.)

Chlorine is slightly less reactive than Chlorine is slightly less reactive than fluorinefluorine

It still reacts with most metalsIt still reacts with most metals Heat is often required to induce Heat is often required to induce

reactionsreactions

Occurrence and preparationOccurrence and preparation

3 Nonmetals: oxygen, nitrogen and 3 Nonmetals: oxygen, nitrogen and sulfur occur in nature such as in the sulfur occur in nature such as in the earth and in the airearth and in the air

Fluorine is found in mineralsFluorine is found in minerals Chlorine is found in underground Chlorine is found in underground

deposits of rock saltdeposits of rock salt Bromine is found in brine wellsBromine is found in brine wells

AllotropyAllotropy

By definition allotropy is when two or more By definition allotropy is when two or more structural forms of an element in the same phase structural forms of an element in the same phase occur in a reaction occur in a reaction

Ex. 2O3(g) -> 3O2(g) Ex. 2O3(g) -> 3O2(g) Phosphorus has several allotropes Phosphorus has several allotropes 2 most common: red phosphorus and white 2 most common: red phosphorus and white

phosphorusphosphorus Sulfur can have more than 20 allotropic forms in Sulfur can have more than 20 allotropic forms in

its solid state, this is done by solid sulfur forming its solid state, this is done by solid sulfur forming different crystalline structuresdifferent crystalline structures

Ex. S8(rhomibic)-> S8(monoclinic)Ex. S8(rhomibic)-> S8(monoclinic)

Examples of Allotropy Examples of Allotropy ProblemsProblems

For the allotropic conversion For the allotropic conversion P(white)-> P(red) P(white)-> P(red) H is -17.6 KJ and H is -17.6 KJ and S is -18.3 J/K At what temperature S is -18.3 J/K At what temperature are the two allotropes in equilibrium?are the two allotropes in equilibrium?

Taking that Taking that H = TH = TSS : T= H/S = -17.6 KJ/-.0183KJ/K =

962K or 690 degrees C

Hydrogen Compounds of the Hydrogen Compounds of the Nonmetals Nonmetals

((Classified by Group)Classified by Group)Group 15Group 15 Group 16Group 16 Group 17Group 17Ammonia, Ammonia, NH3(g)NH3(g)

Water, h20 (l)Water, h20 (l) Hydrogen Hydrogen fluoride, HF(g)fluoride, HF(g)

Hydrazine, Hydrazine, N2H4(l)N2H4(l)

Hydrogen Hydrogen peroxide, H2O2 peroxide, H2O2 (l)(l)

Hydrazoic acid, Hydrazoic acid, HN3(l)HN3(l)

Hydrogen Hydrogen chloride, HCl(g) chloride, HCl(g)

Phosphine, Phosphine, PH3(g)PH3(g)

Hydrogen Hydrogen Sulfide, H2S (g)Sulfide, H2S (g)

Hydrogen Hydrogen bromide , HBr(g)bromide , HBr(g)

Diphosphine, Diphosphine, P2H4 (l)P2H4 (l)

Hydrogen Hydrogen iodide, HI(g)iodide, HI(g)

Oxygen Compounds of Oxygen Compounds of NonmetalsNonmetals

Group 15Group 15 Group 16Group 16 Group 17Group 17

N2O5(g), N2O4(g), N2O5(g), N2O4(g), NO2(g)NO2(g)

OF2(g) O2F2(g)OF2(g) O2F2(g)

N2O3(d), NO(g), N2O3(d), NO(g), N2O(g)N2O(g)

Cl2O7(l), Cl2O6(l)Cl2O7(l), Cl2O6(l)

P4O10 (s), P4O6(s)P4O10 (s), P4O6(s) SO3(l), SO2(g)SO3(l), SO2(g) ClO2(g), ClO(g)ClO2(g), ClO(g)

BrO2(d), BrO(d),BrO2(d), BrO(d),

I2O5(s), I2O5(s), I4O9(s),I2O4(s)I4O9(s),I2O4(s)

Reactions of Nonmetal Oxides Reactions of Nonmetal Oxides with Waterwith Water

When many nonmetals react with When many nonmetals react with water acids are formed water acids are formed

These acids are called acid These acids are called acid anhydridesanhydrides

Ex: SO3(g) +H2O(l) -> H2SO4(l)Ex: SO3(g) +H2O(l) -> H2SO4(l)

Oxoacids and OxoanionsOxoacids and Oxoanions

Group 15Group 15 Group 16Group 16 Group 17Group 17

HNO3, HNO2HNO3, HNO2

H3PO4, H3PO3H3PO4, H3PO3 H2SO4, H2SO3H2SO4, H2SO3 HClO4, HClO3, HClO4, HClO3, HClO2, HClOHClO2, HClO

HBrO4, HBrO3, HBrO4, HBrO3, HBrOHBrO

HIO4, H5IO6, HIO3, HIO4, H5IO6, HIO3, HIOHIO

Acid StrengthAcid Strength

Increasing Oxidation number of the central Increasing Oxidation number of the central atom (HClO< HClO2< HClO3<HClO4)atom (HClO< HClO2< HClO3<HClO4)

Increasing electronegativity of the central Increasing electronegativity of the central atom (HIO<HBrO<HClO)atom (HIO<HBrO<HClO)

X is a highly electronegative atom such as X is a highly electronegative atom such as ClCl

Additional, strongly electronegative Additional, strongly electronegative oxygen atoms are bonded to Xoxygen atoms are bonded to X

Oxidizing and Reducing Oxidizing and Reducing StrengthStrength

1.1. A species in which a nonmetal is in its A species in which a nonmetal is in its highest oxidation state can act only as highest oxidation state can act only as an oxidizing agent, never as a reducing an oxidizing agent, never as a reducing agent. Ex: ClO4 agent. Ex: ClO4 –– ion, where chlorine is in ion, where chlorine is in its highest oxidation state, +7its highest oxidation state, +7

2.2. A species in which a nonmetal is in an A species in which a nonmetal is in an intermediate oxidation state can act as intermediate oxidation state can act as either an oxidizing agent or a reducing either an oxidizing agent or a reducing agent Ex: ClO3- is a much agent Ex: ClO3- is a much stronger oxidizing agent (E*red = +1.442 stronger oxidizing agent (E*red = +1.442 V) than reducing agent (E*ox = -1.226 V)V) than reducing agent (E*ox = -1.226 V)

Oxidizing and Reducing Oxidizing and Reducing Strength (cont.)Strength (cont.)

3. Sometimes, with a species such as ClO3-, 3. Sometimes, with a species such as ClO3-, oxidation and reduction occur together, oxidation and reduction occur together, resulting in disproportionation: resulting in disproportionation:

Ex: 4ClO3-(aq) -> 3ClO4-(aq) +Cl-(aq) E* = Ex: 4ClO3-(aq) -> 3ClO4-(aq) +Cl-(aq) E* = +0.216 V+0.216 V

In general a species in an intermediate In general a species in an intermediate oxidation state is expected to oxidation state is expected to disproportionate if the sum E*ox +E*red is disproportionate if the sum E*ox +E*red is a posotive numbera posotive number

Oxidizing and Reducing Oxidizing and Reducing Strength (cont.)Strength (cont.)

4. The oxidizing strength of an oxoacid or an 4. The oxidizing strength of an oxoacid or an oxoanion is greates at high [H+] (low pH). oxoanion is greates at high [H+] (low pH). Conversely, its reducing strength is greatest at Conversely, its reducing strength is greatest at low [H+] (high pH)low [H+] (high pH)

- when ClO3- acts as an oxidizing agent, the - when ClO3- acts as an oxidizing agent, the H+ ion is a reactant, so increasing its H+ ion is a reactant, so increasing its concentration makes the process more concentration makes the process more spontaneousspontaneous

- when ClO3- acts as a reducing agent, the H+ - when ClO3- acts as a reducing agent, the H+ ion is a product; to make the process more ion is a product; to make the process more spontaneous, [H+] should be loweredspontaneous, [H+] should be lowered