3 Bonds and Compounds Free Online FlashCards

What is a chemical bond?

A chemical bond is an attractive interaction that holds atoms or ions together in a stable arrangement.

What is a molecule?

A molecule is a discrete group of atoms held together by covalent bonds.

What does a subscript show in a chemical formula?

A subscript gives the number of atoms of the preceding element; without a subscript, the count is one. In $\mathrm{H_2O}$, there are two hydrogen atoms and one oxygen atom.

How does ionic bonding hold ions together?

Ionic bonding involves electron transfer, producing oppositely charged ions that attract one another.

What happens to electrons in a covalent bond?

Covalent bonding occurs when atoms share pairs of electrons.

What characterizes metallic bonding?

Metallic bonding involves attractions between metal atoms and mobile electrons shared across the metal.

What properties does metallic bonding help explain?

Mobile electrons help explain why metals conduct electricity and can be shaped without easily breaking apart.

What makes a substance a compound?

A compound contains atoms of at least two different elements chemically combined in fixed proportions.

What does $\mathrm{NaCl}$ represent in solid sodium chloride?

Solid sodium chloride forms an extended arrangement of ions, not separate $\mathrm{NaCl}$ molecules. Its formula represents the simplest whole-number ion ratio, called a formula unit.

What does the outside 2 mean in $\mathrm{Ca(NO_3)_2}$?

Parentheses group atoms that occur together. In $\mathrm{Ca(NO_3)_2}$, the outside subscript means there are two nitrate groups: two nitrogen atoms and six oxygen atoms.

What does a coefficient before a chemical formula count?

A coefficient counts whole particles or formula units and multiplies every subscript. Thus, $\mathrm{3H_2O}$ represents three water molecules.

Why is magnesium chloride written $\mathrm{MgCl_2}$?

The total positive and negative charges must balance. One $\mathrm{Mg^{2+}}$ needs two $\mathrm{Cl^-}$ ions, giving the neutral formula $\mathrm{MgCl_2}$.