Covalent Bonding Flashcards

All 8 cards in this deck

What is a covalent bond?

A shared pair of electrons between two atoms.

Why does a covalent bond hold two atoms together?

Both nuclei are strongly attracted to the shared pair of electrons.

True or false? In a covalent bond, one atom transfers electrons to the other atom.

False. The electrons are shared, not transferred — transfer of electrons is ionic bonding.

Covalent bonding results in the formation of what type of particle?

Molecules.
e.g. chlorine, $Cl_2$, is a simple molecular covalent substance.

What is the typical size (order of magnitude) of atoms and small molecules?

About $1 \times 10^{-10}$ m (0.1 nm).

Which electrons are shown in a dot and cross diagram of a molecule?

e.g. methane, $CH_4$

Only the outer-shell electrons — the inner shell is not involved in bonding.
In $CH_4$ this shows four single bonds, one shared pair between C and each H.

How many pairs of electrons are shared between the two atoms in an oxygen molecule, $O_2$?

Two pairs — a double bond.
In $CO_2$ carbon also forms a double bond with each oxygen.

True or false? A hydrogen atom forms two covalent bonds.

False.

Hydrogen has 1 outer electron and needs only 1 more to fill its shell, so it forms one covalent bond.