PERIODIC TABLEWhat is the periodic table and what does it tell us?

PERIODIC LAW

•When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.

JOHANN DOBEREINER

• 1829: classified some elements into groups of three (triads)• Elements in triad had similar properties

• Triads did not work for all of the elements.

• 1869: published a table of elements

• Organized them in order of increasing atomic mass

• Grouped elements into families

• Each family shared similar properties

• Left Blank spaces for elements he predicted

Dimitri Mendeleev

https://www.youtube.com/watch?v=fPnwBITSmgU

KEY

• REVIEW!

• HOW ARE ELEMENTS ORGANIZED TODAY?

• BY ATOMIC # (#p)

• REMEMBER: No two elements have the same atomic number!

WHAT’S IN THE SQUARE?

• Different periodic tables can include various bits of information, but usually:• atomic number

• symbol

• atomic mass

(refers to “weight” of atom)

• state of matter at room temperature.

SYMBOLS

• All elements have their unique symbol.

• A single capital letter, or a capital letter and one or two lower case letters.

CCarbonCuCopper

ROWS AND PERIODS

• Period = horizontal row

• ACROSS!• There are 7 periods

• Group = vertical column

• UP & DOWN• Also called families

• There are 18 groups

ORGANIZING THE ELEMENTS

Metals

METALS

• 80% of elements are metals

• Located to left of “staircase”

• Properties:• Good conductors of heat

and electricity• Lusterous• Solids at room temperature

(not Hg)• Ductile• Malleable

NONMETALS

• Located in the upper right corner of the periodic table

• Properties opposite of metals

• Gas at room temperature (N, O), solid (S, P), and liquid (Br)

• Poor conductors of heat and electricity

• Solid nonmetals are very brittle

METALLOIDS

Have properties that are similar to metals and nonmetals

• Example: Silicon

• Poor conductor of electric current, silver gray metal-looking, but brittle

EXIT SLIP

1. A horizontal row of blocks in the periodic table is called an?

2. A vertical column of blocks in the periodic table is called an?

3. What are the 3 main groups of elements? Give onecharacteristic of each.

4. How many groups are there on the periodic table?

5. How many periods are there in the periodic table?

MINI QUIZ

1. A horizontal row of blocks in the periodic table is called an?

2. A vertical column of blocks in the periodic table is called an?

3. Is Potassium (K) a metal, nonmetal, or metalloid?

4. Is Chlorine (Cl) a metal, nonmetal, or metalloid?

5. Is Germanium (Ge) a metal, nonmetal, or metalloid?

VALENCE ELECTRONS

VALENCE ELECTRONS

• Electrons in outer energy level – the highest s + p filled in that atom.

• Involved in bonding

THE PERIODIC TABLE TELLS US HOW MANY VALENCE ELECTRONS!

1A

2A

3

A4

A

5A

6

A7

A

8

A

VALENCE ELECTRONS

• Noble gases have 8 v.e.• Called an “octet”

• Atoms want this stability

• Elements gain/lose e- to gain octet and “Be like a Noble Gas”

VALENCE ELECTRONS

• REVIEW-

• Cations – lose e- “paws-itive” charge

• Anions – gain e – negative charge

VALENCE ELECTRONS

• Example:• Cl – has 7 v.e. – wants 8 – what will it do?

• All elements in this family will do the same – and all have a -1 charge

FAMILIES

ALKALI METALS

• Group 1

• Most reactive metals

• Atoms have 1 valence electron

• How will they achieve an octet?

• Lose their 1 v.e.

• Become +1 cation

https://www.youtube.com/watch?v=m

55kgyApYrY

ALKALINE EARTH METALS

• Group 2

• Have 2 valence electrons

• How will they achieve an octet?

• Lose their 2 v.e.

• Become +2 cation

TRANSITION METALS

• Groups 3 -12

• No set charges – “transitioning”

• Ex. Iron (Fe), Mercury (Hg)

HALOGENS

•Group 17

• Most active non-metals

• Have 7 v.e.

• How will they achieve an octet?

• Gain one more v.e.

• Become -1 anion

NOBLE GASES

•Group 18

•Room temp – GAS

•Non-reactive

•Stable – full octet

GENERAL TREND – IMPT!

• METALS

• Want to lose electrons

• Become cations

• NONMETALS

• Want to gain electrons

• Become anions

•Predict the future:• Alkalis have a +1 (Na+)

• Halogens have a -1 (Cl-)

• React with alkali metals to form salts.

• NaCl – this is bonding!!!!

https://www.youtube.com/watch?v=t

bPxwDiX1NU

•Rare earth elements•Many are man made

Lanthanides

Actinides