Matter, Atoms, Elements

A chemistry review

What’s matter? Matter is anything that has mass and

volume Mass is Volume is

Matter is made up of atoms

Atoms Atoms are the simplest form of

matter The structure of atoms determines

the properties of matter An atom has:

Nucleus Electron cloud

Created by G.Baker www.thesciencequeen.net

An atom refresher

An atom has three parts: Proton = positive

◦ Mass about 1 amu Neutron = no charge

◦ Mass about 1 amu Electron = negative

◦ Mass 1/1836 amu

The proton & neutron are found in nucleus

The electrons are in the electron cloud

Picture from http://education.jlab.org/qa/atom_model_03.gif

Elements Elements are made of one kind of

atom Elements cannot be broken into

simpler substances using normal chemical reactions

Elements cannot be broken into simpler substances using physical reactions

Periodic table of elements!

Created by G.Baker www.thesciencequeen.net

Periodic Table

8

OOxyge

n16

Atomic Number:

Number of protons and it is also the number of electrons in an atom of an element.

Element’s Symbol:An abbreviation for the element.Element’s Name

Atomic Mass/Weight:

Number of protons + neutrons.

Atoms of an element don’t always have the same mass number Protons are the same! What’s different?

Isotopes are Examples:

Isotopes

Isotope # p+ # no # e- At no Mass no

Hydrogen-1

Hydrogen-2

Hydrogen-3

LecturePLUS Timberlake9

Isotope notation

Show the mass number and atomic

number

Give the symbol of the element

mass number

23 Na sodium-23

atomic number 11

Atoms all Want:Full outer (valence) electron shellHow do they get it?Atoms form compoundsCompound:

2 or more atoms chemically bonded togetherBond:

Force holding atoms togetherProperties of compound are different from elements

Bonding2 kinds of bond:

IonicCovalent

All bonds happen so atoms can have full valence shell!

Covalent bondingCovalent bonding:

Sharing electron pairsBetween nonmetal atomsMakes moleculesSometimes more than one pair is shared

Double bondTriple bond

Let’s look at an example!Hydrogen! Atno is

Number of valence e-

Is H happy?

NO!

What would make the valence shell full?

Here’s Oxygen!Atno is

Number of valence e-

Is O happy?

NO!

What would make O happy?

Bonding!

H says let’s share!

Another H also shares!

Now everyone’s happy!

We’ve made a compound!

Who’s going to share?

Elements in groups 14-16 and H

Elements in group 17 and H with themselves

Ionic Bonding

Ion:A particle with a charge

Formed when:Atoms gain or lose e-

Gain e- : become negativeLose e- : become positive

Metal and nonmetal bondMetals: left side of periodic tableNonmetals: right side of periodic table

Forming IonsLet’s think about sodium!

Atno is:

Na

Forming IonsHow about chlorine?

Atno is

Forming IonsWhat happens? Na loses e-

Becomes Na+

Cl gains e-Becomes Cl-

Forming IonsWhat happens?

Na+ Cl-

Opposite charged ions are attracted!