Covalent Bonds Flashcards
What are covalent bonds?
Why do atoms do this?
Strong bonds where atoms share electrons to form a full outer shell.
So that they feel like they have a full outer shell and are stable like a noble gas.
Each covalent bond provides what for each atom involved?
So a covalent bond is a …… …… of electrons
An extra shared electron
a shared pair
Hydrogen - covalent bonds
How many extra electrons does H need for a full outer shell? So how many atoms does it bond with?
What does the drawing of the covalent bond look like?
What does the symbol diagram look like?
What does the simple dot and cross diagram look like?
What is the chemical formula for Hydrogen then?
1, 1
The two H atoms in the centre of two circles. The two circles meat like a venn diagram, in between these are a cross and a dot, the atoms’ electrons.
H-H ( - …represents a covalent bond)
H *. H (where *. is a cross above a dot)
H2
Chlorine - covalent bonds
How many extra electrons does Cl need for a full outer shell? So how many atoms does it bond with?
What does the drawing of the covalent bond look like?
What does the symbol diagram look like?
What does the simple dot and cross diagram look like?
What is the chemical formula for Chlorine then?
1, 1
The two Cl atoms in the centre of two circles with dots and crosses all the way round. The two circles meat like a Venn diagram, in between these are a cross and a dot, the atoms’ electrons.
Cl - Cl
Cl *. Cl with the other six dots/crosses around the outside
Cl2
Methane - covalent bonds
How many extra electrons does carbon need for a full outer shell? So how many does must it bond with?
What does the drawing of the covalent bond look like?
What does the symbol diagram look like?
What does the simple dot and cross diagram look like?
What is the chemical formula for methane then?
4, 4
A big circle in the middle, with C inside that, with four crosses around the edge, evenly spaced. Next to each cross is a dot belonging to a hydrogen ring overlapping the carbon ring, like Venn diagrams.
C in the middle with four lines coming out like a cross with Hs on the ends
C with a dot and cross at the top bottom left and right, with an H after each pair of shapes.
CH4
Hydrogen Chloride - covalent bonds
How many extra electrons does Chlorine need for a full outer shell? So how many atoms does it bond with?
What does the drawing of the covalent bond look like?
What does the symbol diagram look like?
What does the simple dot and cross diagram look like?
What is the chemical formula for Hydrogen Chloride?
1, 1
The chlorine atom with a full outer shell but one. One dot is in the Venn gap from a hydrogen atom on its side.
H-Cl
H *. Cl ( with the other three pairs of crosses around it, top bottom and right)
HCl
Ammonia - covalent bonds
How many extra electrons does nitrogen need for a full outer shell? So how many atoms does it bond with?
What does the drawing of the covalent bond look like?
What does the symbol diagram look like?
What does the simple dot and cross diagram look like?
What is the chemical formula for ammonia?
3, 3
N in the middle with one complete pair of crosses at the bottom. On the other three sides the crosses are paired with dots from three H atoms.
H
H- N - H (where the is a line between the top H and the N)
N with one side of two crosses. On the other three sides are one cross and one dot. Hs sit outside the dot and crosses pairs
NH3
Water - covalent bonds
How many extra electrons does oxygen need for a full outer shell? So how many atoms does it bond with?
What does the drawing of the covalent bond look like?
What does the symbol diagram look like?
What does the simple dot and cross diagram look like?
What is the chemical formula for water?
2, 2
O in the middle with two complete pairs of crosses. There are two pairs of dot and cross, the dots belonging to the joint H atoms.
H-O-H
O with two complete pairs of XX, on the other two sides dot X with an H outside of it.
H2O
Oxygen - covalent bonds
How many extra electrons does oxygen need for a full outer shell? So how many atoms does it bond with?
What does the drawing of the covalent bond look like?
What does the symbol diagram look like?
What is the chemical formula for oxygen?
2, 1
Two O atoms next to each other with two sets of XX or . . then in the Venn gap there are . . and XX next to each other, they are sharing 4 between them.
O=O because there are two covalent bonds
O2
What can substances with covalent bonds form?
Simple molecules
The atoms form …. …… covalent bonds to form small …. of several …..
very strong
molecules
atoms
In contrast to a covalent bond how strong are the forces of attraction between molecules made of covalently bonded atoms?
Very weak
What is the result of weak intermolecular forces?
Low melting and boiling points because the molecules can be easily parted.
The stronger covalent bonds between the individual atoms don’t get touched.
What state are most molecular substances in?
Gas or liquid, the can be solid
What do most molecular substances not do?
Conduct electricity as there are no ions so there’s no electrical charge
