science 8H ~ unit 4 ~ periodic table

Atomic number

the number of protons in an atom

Atomic mass

the total number of all protons and neutrons in the nucleus of an atom

Atomic symbol

An abbreviation for an element or atom

isotope

Atoms of the same element with different numbers of neutrons

periods

Horizontal (left to right) rows on the periodic table

groups

Vertical columns on the periodic table

energy level

the distance around the nucleus where electrons may be found

valence electrons

Electrons on the outermost energy level of an atom

The identity of an element is….

The identity of an element is determined by the atomic number

Neutral atoms

Protons = electrons

An atom becomes charged when the number of electrons change

find the number of protons

equal to the atomic number

find the number of electrons

equal to amount of protons (atomic number)

finding the amount of neutrons

Atomic mass - atomic number

If the number of neutrons change, the atom mass will change

periodic trends

The atomic number and atomic mass increase as you go across and down the periodic table

classifying elements

Metals: found to left of the stair step

Nonmetals: found to right of the stair step (except H)

Metalloids: found on the stair step

physical properties of metals

Solids at room temperature (except Mercury)

Good conductors - transfer energy well

Shiny luster - reflect light well

Ductile - can be drawn into wires

Malleable - can be hammered thin

physical properties of nonmetals

Most are gases at room temperature

Poor conductors - do not transfer energy well

Dull luster - do not reflect light well

Brittle - shatter easily

physical properties of metalloids

Have physical properties of both metals and nonmetals

Finding the number of valence electrons

Equal to the ones place digit of the group number