7.6: Metals, Nonmetals, And Metalloids - Chemistry LibreTexts

Chemical Properties of Metals

Metals are electropositive elements that generally form basic or amphoteric oxides with oxygen. Other chemical properties include:

• Electropositive Character: Metals tend to have low ionization energies, and typically lose electrons (i.e. are oxidized) when they undergo chemical reactions They normally do not accept electrons. For example:
  • Alkali metals are always 1+ (lose the electron in s subshell)
  • Alkaline earth metals are always 2+ (lose both electrons in s subshell)
  • Transition metal ions do not follow an obvious pattern, 2+ is common (lose both electrons in s subshell), and 1+ and 3+ are also observed

\[\ce{Na^0 \rightarrow Na^+ + e^{-}} \label{1.1} \]

\[\ce{Mg^0 \rightarrow Mg^{2+} + 2e^{-}} \label{1.2} \]

\[\ce{Al^0 \rightarrow Al^{3+} + 3e^{-}} \label{1.3} \]

Compounds of metals with non-metals tend to be ionic in nature. Most metal oxides are basic oxides and dissolve in water to form metal hydroxides:

\[\ce{Na2O(s) + H2O(l) \rightarrow 2NaOH(aq)}\label{1.4} \]

\[\ce{CaO(s) + H2O(l) \rightarrow Ca(OH)2(aq)} \label{1.5} \]

Metal oxides exhibit their basic chemical nature by reacting with acids to form metal salts and water:

\[\ce{MgO(s) + HCl(aq) \rightarrow MgCl2(aq) + H2O(l)} \label{1.6} \]

\[\ce{NiO(s) + H2SO4(aq) \rightarrow NiSO4(aq) + H2O(l)} \label{1.7} \]

Example \(\PageIndex{1}\)

What is the chemical formula for aluminum oxide?

Solution

Al has a 3+ charge, the oxide ion is \(O^{2-}\), thus \(Al_2O_3\).

Example \(\PageIndex{2}\)

Would you expect it to be solid, liquid or gas at room temperature?

Solutions

Oxides of metals are characteristically solid at room temperature

Example \(\PageIndex{3}\)

Write the balanced chemical equation for the reaction of aluminum oxide with nitric acid:

Solution

Metal oxide + acid -> salt + water

\[\ce{Al2O3(s) + 6HNO3(aq) \rightarrow 2Al(NO3)3(aq) + 3H2O(l)} \nonumber \]