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Periodic Properties.

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Presentation on theme: "Periodic Properties."— Presentation transcript:

1 Periodic Properties

2 Groups The group # is the number assigned to a vertical column on the periodic table. Another name is a Family. 18 groups in the periodic table. Groups 1, 2, 13 – 18 are representative (A) Groups 3 – 12 are transition (B) Some label periodic tables label these groups.

3 Periods 1. The period number is the number assigned to a horizontal row on the periodic table. 2. The number of protons increase from left to right across a period. 3. This number is the atomic number. The period number indicates how many energy levels (rings) each atom has.

4 alkali Alkaline earth Noble gas halogens <---transition > < Inner transition >

5

6 Periodic Table with f-block included
Electron Configurations

7 METALS shiny-luster solids (except Hg) malleable
ductile (stretch to wire) conduct heat & electricity most elements are metals

8 NONMETALS solids, liquids & gases luster-dull brittle poor conductors
upper-right hand corner (& H)

9 Metalliods along stairstep line – between B & Al (Al is not a metalloid!) classified as nonmetals but conduct heat and electricity under certain conditions some metal & nonmetal properties

10 Group 1 - Alkali Metals soft, shiny reacts violently with water
VERY reactive, one valence e- to lose; cation

11 Alkali metals

12 Noble Gases Elements in Group 18 Noble gases are usually unreactive.
This is because they have full valence shells. Elements with full valence shells do not easily gain or lose electrons.

13 Noble Gas Stability Atoms want to gain stability, like the noble gases. Atoms will try to gain or lose electrons to have a full valence shell.

14 Phases of Elements 1. Liquids: You must know: Hg and Br 2. Gases: Don’t memorize, but you need to know their general location. Gases are towards the right side of the periodic table. 3. Solids: All metals, except Hg - mercury

15 Periodic Trends

16 Atomic Radius Atomic radius – size of a neutral atom
Shielding effect – inner energy levels ‘shield’ the outermost electrons from the positive charge pull of the nucleus Atomic radius increases as you move down the groups Great distance (adding energy levels) from nucleus = less pull towards center Decreases as you move left to right More pull from nucleus (more protons), but no new distance EXCEPTION: Noble Gases – much bigger than group 17 – full outer shell

17 Atomic Radii

18

19 Ionic Size (Radius) Ionic Radius - size of an ion
Cations (+) are always SMALLER than neutral atom Nuclear charge the same, less e- = strong pull inwards Anions (-) are always LARGER than neutral atom Nuclear charge the same, MORE e- = less pull inwards Increases as you go down a group Decreases from left to right

20 Ionic Radii

21 Ionization Energy Ionization energy – the energy that is required to remove an e- from an atom Ion – atom which has gained or lost electrons Cation – (+) charged ion (lost e-) Anion – (-) charged ion (gained e-) Decreases as you move down the periodic table Outermost electron gets further from nucleus, easier to pull off Increases as you move across a period No more distance from nucleus, but higher charge = held more tightly

22 Ionization Energy

23 Electronegativity Electronegativity – tendency for an element to have a stronger pull on the shared e- in a covalent bond (values btwn 0-4) Decreases down a group – less likely to keep the shared e- Increases from left to right – more likely to have the shared e-

24 Electronegativity


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