Chemistry flashcards

Unified atomic mass

One twelfth of the mass of a carbon-12 atom

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Relative atomic mass

average mass of the isotopes of an element compared to the unified atomic mass unit

Relative molecular mass

The ratio of weighted average mass of a molecule in a given sample of that molecule compared to the value of the unified atomic mass.

Relative isotopic mass

the mass of a particular atom of an isotope compared to the value of the unified atomic mass unit

Mole

Empirical formula

Simplest ratio of atoms in a compound

Molecular formula

It shows the number and type of each atom in a molecule

Electronegativity

Power of an atom to attract electrons to itself.

Ionic bonding
Metallic bonding
Covalent bonding

The electrostatic attraction between oppositely charged ions
The electrostatic attraction between positive metal ions and delocalised electrons
The electrostatic attraction between the nuclei of two atoms and a shared pair of electrons.

Bond energy

Energy required to break one mole of a particular covalent bond in the gaseous state

Bond length

Internuclear distance of two covalently bonded atoms

Boron trifluoride
structural formula
shape of molecule
Bond angle

BF3
Trigonal Planar
120*

Carbon dioxide CO2

Linear
180*

Methane CH4

Tetrahedral
109.5*

Ammonia

Pyramidal
107*

Water

Non linear
104.5

SF6
name also

Sulfur hexafluoride
Octahedral
90*

PF5

Phosphorus pentafluoride
Trigonal Bipyramidal
3(F-P-F) = 120*
2(F-P)= 90*