PERIODIC TABLE What 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.
1829: classified some elements into groups of three (triads) Elements in triad had similar properties Triads did not work for all of the elements. JOHANN DOBEREINER
Dimitri Mendeleev 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 https://www.youtube.com/watch?v=fpnwbits mgu
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. Cu Copper CCarbon A single capital letter, or a capital letter and one or two lower case letters.
Period = horizontal row ACROSS! There are 7 periods Group = vertical column UP & DOWN Also called families There are 18 groups ROWS AND PERIODS
Metals ORGANIZING THE ELEMENTS
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 METALS
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 one characteristic 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 A 4 A 5 A 6 A 7 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)
Group 17 Most active non-metals Have 7 v.e. How will they achieve an octet? Gain one more v.e. Become -1 anion HALOGENS
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