Atoms and Elements

Periodic Table of Elements

Chart used to organize all known elements

Nucleus

the center of an atom, which contains the protons and neutrons

Element

A pure substance made of only one kind of atom

Atom

the smallest particle of an element that retains the properties of that element

Bohr Model

model of an atom that shows electrons in circular orbits around the nucleus

Symbol for aluminum

Al

Symbol for sodium

Na

Element used in balloons

Helium

Period

A horizontal row of elements in the periodic table

Group

A vertical column in the periodic table, also known as a family of elements

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

Electron

A subatomic particle that has a negative charge

Atomic number

the number of protons in the nucleus of an atom; identifies the atom.

Element Symbol

the abbreviation of an elements name; 1 or 2 letters, first letter is always capitalized, second is never capitalized

Atomic mass

The decimal number on an element square; Number of protons and neutrons

Electron orbit

the path of an electron around the nucleus of an atom. Electrons are found here.

Subatomic particles

smaller particles that make up atoms

Compound

Two or more different elements joined by chemical bonds

18

The number of groups on the Periodic Table

7

The number of periods on the Periodic Table

metals

elements that are shiny, ductile, and good conductors of heat/electricity

noble gases

the elements in Group 18 on the periodic table

nonmetals

elements that are poor conductors of heat/electricity, dull, brittle

element square

the block on the periodic table that tells information about a specific element.

metalloids

Elements that have properties of both metals and nonmetals.

family

a group of elements on the periodic table that share similar properties

2

The number of electrons that can fit in the first shell

8

The number of electrons that can fit in the 2nd shell

atomic mass - atomic number

formula for calculating the number of neutrons

protons and neutrons

The nucleus of an atom contains

protons and electrons

Atomic number is equal to the number of...

Dmitri Mendeleev

Russian chemist who developed a periodic table of the chemical elements and predicted the discovery of several new elements