Periodic table Flashcards
What is the atomic radius
The distance between the nucleus and the outermost electron
What is the trend with atomic radius in the periodic table
Atomic radius increases down a group and decreases along a period
What is electronegativity
The ability of an atom to attract electrons from another compound
What is the trend with electronegativity in the periodic table
Increases along a period and decreases down a group
Why does electronegativity decrease down a group
Atomic radius increases down a group as there is more electrons, therefore there is a weaker attraction between electrons and the nucleus, so harder to attract electrons
What element has the highest electronegativity
Fluorine
Is a molecule polar or non-polar when it has a large electronegativity difference
Polar
This is because the atom with the higher electronegativity has a stronger attraction for the bonding pair of electrons.
This means there is an unequal distribution of electrons in the covalent bond, leading to partial charges.
Is a molecule with little to no electronegativity difference polar or non-polar?
Non-polar
This is because the electrons are equally shared in the covalent bond.
How are ionic bonds formed?
Between a metal and non-metal
The atoms have an even larger electronegativity difference, leading to the metal donating electrons to the non-metal with a larger electronegativity
The Pauling scale can be used to determine if a bond is covalent polar, covalent non-polar or ionic, what are the values?
<1.0 - Non-polar covalent
1.0-2.0 - Polar covalent
>2.0 - Ionic
What is group 1 and what is their charge?
Alkali metals
+1 charge
What is group 2 and what is their charge?
Alkaline metals
+2 charge
What are metals in group 3-12 known as and what are their charges?
Transition metals
Charges range from +1-+7
High melting points
What is group 13/3 and what are their charges?
Beginning of metalloids
+3 Charge
What is group 14/4 and what are their charges?
Metals, one metal and one metalloid
+4/-4 Charge
Likely to form +2 charged ions down the group
E.g. Pb is usually +2 charge
Si and Ge are used as semi-conductors
What is group 15/5, 16/6, 17/7 and what are their charges?
Group 5 -3 charge
Group 6 -2 charge
Group 7/Halogens -1 charge
What are energy level rules?
- Electrons fill lowest level orbitals first
E.g. 1s is filled before 2s - There is a maximum of two electrons per orbital
- Electrons in the same orbital must be opposite spins