Unit 1 Flashcards
(30 cards)
How are elements arranged in the periodic table across the rows
increasing atomic number
How are elements arranged in the periodic table down a group
common number of outer electrons
What can we predict from the periodic table
Reactivity, Physical Properties and type of bonding
What is covalent radius
it is a measure of the size of an atom
across a period left to right what happens to the covalent radius
it decreases
Why does the covalent radius decrease across a group, left to right
- increase in nuclear charge
- increase in protons
down a group what happens to the covalent radius
it increases
why does the covalent radius increase down a group
- increase screening effect
what is the first ionisation energy
- the energy required to remove one mole of electrons from one mole of a gaseous atom
what happens too the ionisation energy across a group left to right
it increases
why does the ionisation energy increase left to right
- an increased number of protons
- an increase of attraction between protons and electrons
what happens to the ionisation energy down a group
it decreases
why does ionisation energy decrease down a group.
- increase screening effect
what happens to the electronegativity across a group left to right
it increases
why does the electronegativity increase across a group
- increased number of electrons in the outer shell
- increased attraction to protons in the nucleus
what happens to the electronegativity down a group
it decreases
why does the electronegativity decrease down a group
increase shielding effect
what is electronegativity
the measure of attraction of the atom involved in a bond, has for the electrons in the bond
what are the intramolecular bonding
- covalent molecular
- covalent networks
- ionic bonding
- metallic bonding
name the VdW forces
- hydrogen bonding
- LdF
- permanent dipole - permanent dipole interactions
what is the difference between pure covalent/ non-polar and polar
pure/ non-polar covalent is when two atoms share bonding electrons equally. The electronegativity is zero on these covalent bonds.
polar covalent is when electrons are unevenly shared between bonding atoms. Electronegativity is not zero.
what is the bonding continuum
pure covalent bonding and ionic bonding can be seen as the opposite ends of the spectrum, with polar covalent in-between.
the difference in electro negativities allow us to see an indication of ionic characters
what is the weakest VdW force
LdF
what happens in an LdF force
electrons are unevenly distributed resulting in a temporary induced dipole.
the strength of LdF’s increase when the number of electrons in an atom or molecule increases
