Covalent bonding Flashcards

All 7 cards in this deck

What is a covalent bond?

A shared pair of electrons between two atoms.

What are the steps to draw a dot and cross diagram for a small covalent molecule?

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

1. Count the outer shell electrons: O has 6, each H has 1.
2. Overlap the shells so each shared pair completes the outer shells: O shares one pair with each H.
3. Show the result: 2 bonding pairs in the overlaps and 2 non-bonding pairs on the oxygen.

What three kinds of structure can covalently bonded substances have?

Small molecules, very large molecules such as polymers, and giant covalent structures such as diamond and silicon dioxide.

In a displayed (line) structure of a molecule, what does one line between two atoms represent?

A single covalent bond — one shared pair of electrons.

What are the steps to deduce the molecular formula of a substance from a dot and cross or ball and stick diagram?

e.g. a diagram showing 3 carbon, 6 hydrogen and 1 oxygen atom

1. Count the atoms of each element: C 3, H 6, O 1.
2. Write the symbols with the numbers of atoms as subscripts (no number for 1): $\mathrm{C_3H_6O}$.

True or false? The covalent bonds between the atoms inside a small molecule are weak.

False. Covalent bonds between atoms are strong.

True or false? Polymers are covalently bonded substances made of very large molecules.

True. Some covalently bonded substances have very large molecules, such as polymers.