3 Periodicity Flashcards
factors that affect an element’s physical properties:
-
Number of protons in nucleus
More protons → greater attraction force → harder to lose e- -
Number of electron shells
More shielding → smaller attraction force → easier to lose e- -
Distance of electrons from nucleus
Further → smaller attraction force → easier to lose e-
describe the periodic trend of atomic/ionic radius
-
Increases down a group
More shells -
Decreases across a period
More protons → stronger attraction force → shells pulled closer to nucleus - -ions are larger than their parent atom as they gain e-; +ions are smaller as they lose e- and outer shell
define electronegativity + describe the periodic trend
Electronegativity is the atom’s ability to attract bonding electrons
* Decreases down a group
Further from nucleus + more shielding → weaker force of attraction
* Increases across a period
More protons → stronger force of attraction → shells pulled closer → even stronger force of attraction
define electron affinity + describe the periodic trend
Electron affinity is the energy change when one mole of electrons is added to one mole of gaseous atoms to form one mole of gaseous ions:
attraction → energy change → electron affinity
* Decreases down a group
Further from nucleus + more shielding → weaker force of attraction → less energy released
* Increases across a period
More protons → stronger force of attraction → shells pulled closer → even stronger force of attraction → more energy released
define ionization energy + describe the periodic trend
Ionization energy is energy needed to remove 1 mole of electron from its atom
* Decreases down a group
Further from nucleus + more shielding → weakerattraction force → less energy needed to overcome the attraction and remove e-
* Increases across a period
More protons → stronger attraction force → shells pulled closer → even stronger force of attraction → more energy needed to overcome the attraction and remove e-
* G3 has higher ionization energy than G2
p-orbitals have higher energy than s-orbitals
* Paired electrons are easier to remove due to
repulsion between them
Why do successive ionization energies increase (3rd > 2nd > 1st)?
- Inner electrons are closer to nucleus → less shielding + shorter distance → stronger attraction → more energy needed to remove
- Number of electrons decrease → less repulsion between electrons → more energy needed to remove
What is the total number of ions in one formula unit of Fe2(SO4)3?
5
Fe x 2 + SO4 x 3
What happens to the physical & chemical properties of the elements as you go down G1?
* Density
* Metallic bond
* Reactivity
- More p+n → greater mass → more dense
- More shells → electrons further from nucleus + more shielding → weaker attraction force → weaker bond → easier to lose e- → more reactive
What are the characteristics of Halogens?
- Non-metals with toxic, colored vapors
- Form ions by gaining e- (reduced) → oxidizing agent
- Diatomic molecules
color of F2 gas
yellow
color of Cl2 gas
green
color of Br2 gas/liquid
brown
color of iodine solid
nearly black
what factors affect the bond strength of covalent bonds?
- longer bonds = weaker (bigger atomic radius → increased distance between the nuclei and the shared pairs of bonding electrons → weaker electrostatic attraction → weaker bond)
- multiple bonds = stronger (more shared electrons between the atoms → stronger electrostatic attraction → nuclei closer together → shorter also = stronger)
a colvalent bond with 2 bonding pairs
* name
* bond angle
linear
180˚
