1

Properties of Metal, Nonmetals,and Metalloids

Metals, Nonmetals and Metalloids

• The individual atomic properties of atoms can be related to the observed macroscopic behavior of the elements. The trends we observe across the periodic table help explain chemical behavior.

– Metals tend to have low ionization energies and form (+) ions.– Nonmetals have high electron affinities and tend to form (-) ions.– Compounds of metals and nonmetals tend to be ionic substances.– Compounds of nonmetals are molecular substances.

– Most metal oxides are basic in water.(what are some examples?)– Most nonmetal oxides are acidic in water.(what are some

examples?)

Metalloids

• Have some characteristics of metals, some of nonmetals.

• For instance, silicon looks shiny, but is brittle and fairly poor conductor.

2

Alkali Metals (1A)

Their reactions with water are famously exothermic.

Produce bright colors when placed in flame

SodiumandPotassiuminWater.MOV

• Metals form basic oxides since they contain a basic anion, O2–.• Metal oxide + water —> metal hydroxide

Na2O(s) + H2O(l) —> 2 NaOH(aq) MolecularO2–(aq) + H2O(l) —> 2 OH–(aq) Net-ionic

• Metal oxide + acid —> salt + water (Acid-base rxn!)Fe2O3(s) + 6 HNO3(aq) —> 2 Fe(NO3)3(aq) + 3 H2O(l)

• Nonmetals form acidic oxides.• Nonmetal oxide + water —> acid

CO2(g) + H2O(l) —> H2CO3(aq)SO3(g) + H2O(l) —> H2SO4(aq)

• Nonmetal oxide + base —> salt + water (Acid-base rxn!)SO3(g) + 2 NaOH(aq) —> Na2SO4(aq) + H2O(l)

PeriodicTrendAcidBaseOxide.MOV

1. Would you expect aluminum oxide to be a solid, liquid, or gas at room temperature? (b) Write the balanced chemical equation for the reaction of aluminum oxide with nitric acid.

2. Write the balanced chemical equation for the reaction between copper(II) oxide and sulfuric acid.

3. Write the balanced chemical equation for the reaction of solid tetraphosphorus hexoxide with water.

Alkali Metals (Gr 1A)• Very reactive because of low ionization energy. Easily oxidized.• Found only as compounds in nature. Low melting points and densities

when pure.• All will form metal hydrides: 2 Na(s) + H2(g) —> 2 NaH(s)• All will react with water to form hydroxides and H2:

2 Na(s) + 2 H2O(l) —> 2 NaOH(aq) + H2(g)

• Reactivity increases down the column, why? m.p trends?

3

Alkaline Earth Metals (Gr 2A)

• Have higher densities and m.p’s than alkali metals. Not as reactive.

• Low IE’s.• Generally don’t form metal hydrides.• Ca, Sr and Ba react with water at room temperature:

Ca(s) + 2 H2O(l) —> Ca(OH)2(aq) + H2(g)• Reactivity increases down the column. Why?

1.Write a balanced equation that predicts the reaction of cesium metal with (a) Cl2(g), (b) H2O(l)

2. Bi2O3 is a basic oxide. Write a balanced chemical equation for its reaction with dilute nitric acid. If 6.77 g of Bi2O3 is dissolved in dilute acidic solution to make up 500 mL of solution, what is the molarityof the solution of Bi3+ ion?

The Oxygen Group (6A)

• Oxygen comes in two allotropes, O2(g) and O3(g) ozone.• Oxygen is easily reduced, very good oxidizing agent.

(Negative 1st electron affinity.)• Oxygen forms two less common ions:

Peroxide O22– as in H2O2(aq)

Superoxide O2– as in KO2(s)

• Sulfur is similar to oxygen except much less reactive.• Sulfur comes as a ring in nature, S8(s).

115

The Halogens (7A)

• Very reactive, high electron affinities. Easily reduced. Very good oxidizing agents.

• Fluorine will react with almost anything to become F–:2 F2(g) + SiO2(s) —> SiF4(g) + O2(g)6 F2(g) + 2 Al2O3(s) —> 4 AlF3(s) + 3 O2(g)

PhysicalPropsofHalogens.MOV

4

The Noble Gases• Very unreactive. High ionization

energies and positive electron affinities. Completely filled p shell gives higher than expected electron stability.

• However, some compounds have been made with Xe and Kr, the larger noble gasses under extreme conditions.

XeF4(s)