Science 8

ATOMS

Non-metals

Low conductivity

nonmetals have a \___ variety of properties

wider

Non metals are

poor conductors of heat and electricity

families containing nonmetals

carbon family

diatomic molecule

A molecule consisting of two atoms

Halogens

Contains nonmetals

Noble Gases (Group 18)

nonreactive gases

Metalloids

Elements that have properties of both metals and nonmetals. solid at room temp

semiconductor

A substance that can conduct electricity under some conditions

Metals

Elements that are good conductors of electric current and heat.

Physical properties of metals are

luster, ductility, malleability, being good conductors of heat and electrical current,

Luster

The way a mineral reflects light

malleable

easy to shape or bend

ductile

can be drawn into wires

thermal conductivity

The ability of an object to transfer heat

electrical conductivity

The ability of an object to carry electric current

Reactivity

How readily a substance combines chemically with other substances.

Metals are classified as

alkali metals, alkaline earth metals, transition metals,

alkali metals

Group 1

Alklaline Earth Metals

Group 2

transition metals

Groups 3-12

Dimitri Mendeleev sorted the elements based on their

on the melting point

atomic mass

The average mass of all the isotopes of an element ( proton and neutrons)

Mandeleev's saw that there were a \__________when arranging elements from atomic mass.

pattern of properties

properties of elements do what?

repeat

Called periodic table because

repetition of properties

Modern Periodic Table

elements are arranged in order of increasing atomic number

the periodic table includes

the atomic number

chemical symbol

A one or two letter representation of an element

rows on the periodic table

periods

colomns in a periodic table

groups

there are \___ periods and \___ groups

7

properties of an element

can be predicted from its location in the periodic table

Metals are shown on the...

left

nonmetals are shown on the..

right

Metalloids

elements with properties that fall between those of metals and nonmetals

atom

smallest particle that can be considered a element.

atomic theory grew as series of models that developed from ______

experimental evidence

electrons

negatively charged particles

nucleaus

small, positivily charged part of an atom

protons

posotivley charged particles

energy level

electrons movement it related too this

neutron

neutrally charged

at the center of the atom is a tiny dense ___ __containing__ __ __and__ _____. Surrounding the__ ____ __is a__ ____ __region of moving__ ____.

neucleus, protons, neutrons, nucleus, electrons

atomic number

mass of atom, electrons: protons

isotopes

same number of protons but different number of neutrons

mass number

sum of protons and neutron in the atom; isoptopes are defined by this.