Atomic Structure & Bonding Flashcards
What forms positive ions?
Metals losing electrons
What forms negative ions?
Non-metals gaining electrons
What is a molecule?
Two or more atoms bonded together
What is a compound?
Two or more different atoms bonded together
What is the shape of the molecule if consists of 2 atoms?
Linear
What is the shape of the molecule if it consists of 3 atoms?
Angular
What is the shape of the molecule if it consists of 4 atoms?
Trigonal Pyramidal
What is the shape of the molecule if it consists of 5 atoms?
Tetrahedral
When is a covalent bond formed?
When two non-metal atoms join together
What is a covalent bond?
A shared pair of negative electrons between two non-metal atoms
What holds a covalent bond together?
The mutual attraction by both positive nuclei on the negative shared pair of electrons
Why are atoms neutral?
They contain the same number of positive protons and negative electrons so they cancel each other out
What are the three elements that naturally exist as covalent networks?
Boron, Silicon and Carbon
What are the two common forms of carbon?
Diamond and Graphite
What does delocalised mean?
Free to move
Why is Graphite the only covalent substance that conducts electricity?
The layers of carbon rings are separated by layers of delocalised electrons
What is an ionic bond?
The electrostatic attraction between oppositely charged ions
How is an ionic bond formed?
Between metals and non-metals
What happens when covalent molecular substances are heated?
The weak forces are broken. This doesn’t require a lot of energy
What happens when an ionic lattice is heated?
The electrostatic attraction between the positive and negative ions is broken. This takes a lot of energy
What happens when a covalent network is heated?
Strong covalent bonds are broken. This takes a lot of energy
What are the melting and boiling points of each bonding type?
Covalent Molecular- Low
Covalent Network- High
Ionic Lattice- High
Which of the bonding types conducts electricity?
Ionic Lattices as a solution
What does a low melting point tell you about a molecule?
Only weak forces of attraction are being broken
What does a high melting point tell you about a molecule?
Strong bonds are being broken
What can be said about the solubility of covalent molecular compounds?
They are generally soluble in non-aqueous solvents
What can be said about the solubility of ionic substances?
They are generally soluble in aqueous solvents
What can be said about the solubility of covalent network substances?
They are insoluble in any solvent
What does aqueous mean?
Water is present
