The AtomSmallest unit of an element that can exist aloneGreek for “uncuttable”

Anatomy of an Atom: Electrons, Protons, NeutronsThe Nucleus

ProtonPositive chargeDetermines the atomic numberNumber of Protons determines the number of Electrons

NeutronNo chargeAtomic weight - # of Protons = # of Neutrons

Atomic Structure

ElectronsNegative chargeAtomic number tells you the number of

electronsResides in the “shells”, orbits, or levels

Atomic Structure

Organized representation of the chemical elements Dimitri Mendeleev

February 17, 1869 63 elements

113 elements Row (Period)

Left to right w/ increasing atomic number Number from 1 to 7

Columns (Family) Number of electrons in the outer orbit

Groups A Group (Representative elements) B Group (Transition elements) Group VIIIA

Noble or inert gases Metals, Semiconductors, & Nonmetals

More on this later – stay tuned

The Periodic Table

The ElementSymbolAtomic number

Total number of electronsTotal number of protons

Electrical chargeElectrons – minusProtons – plusNeutrons – no charge

Atomic weight (Nucleus)Protons + Neutrons = atomic weight

The Periodic Table

Electron ConfigurationEnergy Levels (Shells)

Level I – 2Level II – 8Level III – 8 (first 20 elements) (18)Level IV – 32

The Periodic Table

Putting it all together . . .

Sodium NaAtomic # - 11

Level I (Shell) - 2Level II - 8Level III – 1

The Periodic Table

Try this one . . .

Chlorine Cl

The Periodic Table

Chlorine ClAtomic # 17

Level I – 2Level II – 8Level III – 7

The Periodic Table

What does the Periodic Table Tell Us?Element symbol & nameAtomic Number of the element

Number of electronsNumber of protons

Number of neutronsNumber of electrons in the outer

shellAtomic weight

The Periodic Table

Metals, Nonmetals, & Semiconductors80% of the elements are metals

IonAn element with an unbalanced electron

charge – either plus or minusPositive ions – lose electrons

MetalsNegative ions – gain electrons

Non-metalsRemember – the number of protons determines the

charge

The Periodic Table

IonsWhen the number of protons is

greater than the number electrons it is a positive (+) charged ion.

When the number of electrons is greater than the number of protons it is a negative (-) charged ion.

The Periodic Table

MetalsElements with 1 – 3 electrons to

losePositive ion

Non-metalsElements with 1 -3 electrons to

gainNegative ion

The Periodic Table

Check this out . . .

http://www.vanderkrogt.net/elements

The Periodic Table