1. Ch. 6 The Periodic Table

2. Mendeleev’s Periodic Table
Elements in the periodic table are arranged by repeating properties
Arranged in order by increasing atomic mass
Left spaces where he predicted future elements would fit

3. Mendeleev’s Periodic Table

4. Periodic Law
In the modern periodic table, elements are arranged in order by increasing Atomic Number
7 horizontal rows called periods
Each period corresponds to a principle energy level
Elements within a column (group) have similar properties

5. Periodic Law
States: when elements are arranged by increasing atomic number, there is a periodic repetition of their physical and chemical properties

6. Metals, Nonmetals, Metalloids

7. Metals 80% of the periodic table is metals
Good conductors of heat and electricity
Malleable- can be shaped
Ductile- can be drawn into wires
Lustrous
Solids at room temperature (except Hg)

8. Nonmetals Poor conductors of heat and electricity Not malleable
Not ductile
dull

9. Metalloids
Generally has some properties of a metal, some of a nonmetal

11. Lithium (Li) Sodium (Na) Potassium (K) Alkali Metals 1s22s1
1s22s22p63s1
Potassium (K)
1s22s22p63s23p64s1

12. Alkaline Earth Metals Beryllium (Be) 1s22s2 Magnesium (Mg)
1s22s22p63s2
Calcium (Ca)
1s22s22p63s23p64s2

13. Halogens Fluorine (F) 1s22s22p5 Chlorine (Cl) 1s22s22p63s23p5
Bromine (Br)
1s22s22p63s23p64s23d104p5

14. Noble Gasses 1s22s22p6 1s22s22p63s23p6 1s22s22p63s23p64s23d104p6
Neon (N)
1s22s22p6
Argon (Ar)
1s22s22p63s23p6
Krypton (Kr)
1s22s22p63s23p64s23d104p6

15. Trends in Atomic Size
Atomic radius is ½ the distance between the nuclei of 2 like atoms
As you move DOWN a group, atomic size increases
As you move LEFT to RIGHT across a period size decreases

16. Why?
As you move across the period you gain electrons but you also gain protons. More + protons hold their electrons tighter
As you move down the group you gain more electrons which are in electron orbitals further away from the nucleus. The nucleus has less influence the further out you move.

18. Trends in Ionization Energy
Ionization Energy is the energy required to remove 1 electron from a gaseous atom
As you move DOWN a group ionization energy DECREASES
As you move LEFT to RIGHT across a period ionization energy INCREASES

19. Why?

20. Trends in Electronegativity
Electronegativity is the tendency of an atom to attract electrons in a compound
As you move DOWN a group Electronegativity DECREASES
As you move LEFT TO RIGHT across a period Electronegativity INCREASES

21. Summary of Periodic Trends