Covalent Bonding - Topic 1 Flashcards
1
Q
Describe covalent bonds:
A
- non-metal + non-metal
- molecules: simple, giant
- Two or more non-metals join together by covalent bonding. Molecules are formed which do not have a charge.
- Molecules are only ever found in covalent compounds, ionic compounds contain ions
2
Q
What does covalent bonding result in?
A
covalent bonding results in the formation of molecules
3
Q
Atom:
A
- An atom is the smallest particle of an element that can exist or take part in a chemical change.
- Can’t be further divided into any other substances
4
Q
Molecule:
A
- A group of atoms held together by covalent bonding
- Two or more non-metal atoms chemically joined together, the group of combined atoms is called amolecule
5
Q
Info about molecules and covalent bonding:
A
- In some gaseous elements, single atoms cannot exist on their own at ordinary temperatures: in these elements the free-moving particles consist of pairs of atoms
- The two atoms forming a pair (a MOLECULE) are joined together by a chemical “bond”. - Such substances are said to be diatomic
- Elements which Occur as Diatomic Molecules: hydrogen H2, nitrogen N2, oxygen O2, Fluorine F2, Chlorine Cl2, Bromine Br2, Iodine I2
6
Q
Different types of molecules:
A
- When molecules contain atoms of the same type – these are molecules of anelement
- When molecules contain atoms of different type – these are molecules of acompound
7
Q
How are covalent bonds formed?
A
- each atom donates one electron to the bonding pair of electrons, which make up the covalent bond
- by doing this each atom has the same electron structure as a noble gas
- sometimes atoms cans hare two or three electron pairs to form double and triple covalent bonds
- so the atoms share electron pairs to achieve full outer shells
8
Q
What is covalent bonding:
A
- between two or more non-metal elements
- these elements generally want to share electrons to gain a full outer shell
- a covalent bond consists of a shared pair of electrons
- sometimes covalent bonds are called molecular/intramolecular
9
Q
What are the two types of covalent substance?
A
- simple covalent
- giant covalent
10
Q
What do simple covalent substances consist of?
A
- e.g. H20, CH4, NH3, CO2, O2
- composed of tiny separate particles called molecules
- contain several atoms bonded strongly together by covalent bonds
11
Q
What do giant covalent substances consist of?
A
- e.g. diamond and graphite
- contain millions of atoms bonded by many strong covalent bonds to form a larger molecule or lattice
12
Q
Covalent bond:
A
a shared pair of electrons between atoms
13
Q
How is a covalent bond formed?
A
a covalent bond is formed when a pair of electrons is shared between atoms
14
Q
What is the typical size (order of magnitude) of atoms and molecules?
A
- Simple molecular substances consist of molecules in which the atoms are joined
by strong covalent bonds - Therefore, atoms are smaller than small molecules
