Bonding Flashcards
(21 cards)
An element
Substance that can’t be split up into simpler substances by chemical means
Compound
Substance that’s made up of 2/ more elements combined chemically
Atomic no.
No of protons in the nucleus of that atom
Mass no.
Sum of protons+neutrons in the nucleus of an atom of that element
Octet Rule
When bonding occurs, atoms want to reach 8 electrons in their outer shell
Ion
A charged atom/ group of atoms
Ionic bond
Force of attraction between oppositely charged ions in a compound. Always formed by the complete transfer of electrons from one atom to another
Transition metal
Forms at least one ion with a partially filled d sublevel
Molecule
Group of atoms joined together. The smallest particle of an element that can exist independently
Valency of an element
The no. of atoms of hydrogen or any other monovalent element with which each atom of the element combines
Sigma bond
Formed by the head-on overlap of two orbitals
Pi bond
Formed by the sideways overlap of p orbitals
Electronegativity
The relative attraction that an atom in a molecule has for the shared pair of electrons in a covalent bond
Polar covalent bond
A bond in which there is unequal sharing of the pair of electrons. This causes one end of the bond to be slightly more positive (delta+) and the other to be slightly more negative (delta-)
Intramolecular bonding
Bonding that takes place within a molecule, it holds the atoms together. E.g. Covalent and polar covalent bonding
Intermolecular forces
Attractive forces between molecules. E.g Van der Waals forces, dipole-dipole forces and hydrogen bonding
Van der Waals forces
Weak attractive forces between molecules resulting from the formation of temporary dipoles. The only forces of attraction between non-polar molecules
How can a molecule with polar bonds be non-polar?
They are symmetrical molecules where the centre of the partial negative charge coincides with the partial positive charge
Predict the shape of boron trifluoride
Trigonometry planar (3 pairs of electrons all in the same place and no lone pairs)
What does an increase in electronegativity value indicate?
There’s an increasing no. of protons, atomic mass and nuclear charge
And a decrease in atomic radius
How did Mendeleev predict the properties of unknown elements?
He used the properties of known elements to predict the properties of other elements f the same group. He arranged the elements in order of increasing atomic mass and left gaps in his table for undiscovered elements
