Covalent bonding (small molecules) Flashcards
What is covalent bonding?
The sharing of electrons between two non-metals
What is a molecule?
A group of two or more atoms joined together by covalent bonds
What is the formula of a hydrogen molecule?
H2
The formula for ammonia is NH3. What does this mean?
Ammonia contains one nitrogen atom and three hydrogen atoms.
What is the chemical formula for this covalent molecule?
H2
What is the name of this covalent molecule?
Ammonia (NH3)
How many covalent bonds are in a molecule of ammonia?
Three
How many electrons does carbon need to gain a full outer shell?
Four
How many covalent bonds can a nitrogen atom form?
Three
Nitrogen has 5 electrons in its outer shell.
Hydrogen has 1 electron in its outer shell.
Sketch a complete dot and cross diagram for ammonia, showing only the electrons in the outer shell of the atoms.
Carbon has four electrons in its outer shell.
Hydrogen has 1 electron in its outer shell.
Draw a dot and cross diagram for methane, CH4.
What is the formula and name of this molecule?
Formula: H2O
Name: water
Oxygen has a double bond (two shared pairs of electrons).
How can you show this in a formula?
O=O
Nitrogen has a triple bond (three pairs of shared electrons).
How can you write this as a formula?
N≡N
Why are most covalent molecules gases at room temperature?
- They have low melting and boiling points
- Because there are weak forces between the molecules
