Covalent Bonding Flashcards

All 9 cards in this deck

What is a covalent bond?

A shared pair of electrons between two atoms.

What is meant by the term molecule?

Two or more atoms joined together by a covalent bond (a shared pair of electrons).

True or false? In covalent bonding, electrons are transferred from one atom to the other.

False. In covalent bonding the electrons are shared between the two atoms; transfer of electrons is ionic bonding.

What type of bonding holds the atoms together in a molecule of hydrogen chloride, HCl?

Covalent (not ionic or metallic).

What is the typical size (order of magnitude) of an atom or a small molecule?

About $1 \times 10^{-10}$ m.

What are the steps to draw a dot and cross diagram of a simple molecule (outer shell electrons only)?

e.g. water, $\mathrm{H_2O}$

1. Draw the outer-shell electrons of each atom: O has 6, each H has 1.

2. Overlap each outer shell to make a shared pair in each overlap: 2 shared pairs (one O–H bond each).

3. Show the atom's remaining outer electrons: 4 electrons left on the O only.

How many electrons are shared in a double bond?

e.g. the O=O bond in an oxygen molecule

4 electrons — two shared pairs.

In the formula of a molecule, what does the small number written after an element's symbol tell you?

e.g. the 2 in $\mathrm{H_2O}$

How many atoms of that element are in one molecule.

e.g. one molecule of $\mathrm{H_2O}$ contains 2 hydrogen atoms (and 1 oxygen atom).

Why do non-metal atoms share electrons to form covalent bonds?

Sharing pairs of electrons gives each atom a full outer shell of electrons.