chem unit 2

Groups on periodic table

Vertical columns

Periods on periodic table

Horizontal rows

Elements in the periodic table are arranged according to their

Atomic number (number of protons)

General location of metals on periodic table

Left of “staircase” dividing line (except hydrogen)

General location of nonmetals on the periodic table

Right of the “staircase” dividing line

The 6 metalliods on the periodic table

B,Si,As,Sb,Te,Ge

Group 18 on periodic table

Noble gases:gases at room temperature, full valence shell, very stable

Properties of metals

Malleable, Ductile and good conductors of heat and electricity

Properties of nonmetals

Dull, brittle, poor conductors of electricity and heat

STP stands for

Standard temperature (273K) and pressure (101.3 kPa)

Elements have similar properties jf they are the same

Group/family/column on the Periodic Table

Allotropes

Different molecular structures of the same element with different properties (ex. Diamond and graphite are two allotropes of carbon)

Octet rule

When forming compounds atoms tend to lose or gain electrons to achieve the electron configuration of a noble gas(usually 8 valence electrons)

Halides (Halogens)

Group 17 elements on the periodic table (F,Cl,Br,I)

Electronegativity

The ability of an atom to attract electrons when the atom is in a compound

Atomic radius

Size of an atom

Ionic radius

Size of and ion (ion is after an atom has lost or gained electrons)

Ionization energy

The amount of energy required to remove an electron from an atom

Elements that are liquid at STP

Bromine(Br) and Mercury (Hg)

Elements that are gases at STP

H,N,O,F,Cl and the noble gases (group 18 elements)

The trend of electronegativity across a period and down a group

Electeonegativity increases across a period and decreases across a group

Trend of atomic radius across period and down a group

Atomic radius decreases across period and increase down group

Trend of ionization energy across period and down group

Increase across period decrease down group