P. Sci. Unit 8 Periodic Table Chapter 5

Periodic Law Properties of elements tend to change in a regular pattern when elements are arranged in order of increasing atomic number, or number of protons in their atoms.

Periodic Table The periodic table is arranged in- Periods (horizontal) rows –There are 7 periods Groups families (vertical) columns –There are 18 columns

Metals all elements on the left side of the table (except Hydrogen) Non - Metals all elements on the right side of the table

Hydrogen Hydrogen (1) – 90% of the atoms in the universe – (diatomic – two atoms of the same element in a covalent bond – H,N,O,F,Cl,Br,I). Very reactive, both covalent and ionic bonds can form

Metalloids elements that share both metal and non-metal characteristics – the elements on both sides of the stair-step line except aluminum. Also called semiconductors

Alkali Metals (Column 1 except Hydrogen) – the most reactive group – do not occur in nature in their elemental form. Has one electron in its outer energy level All (including hydrogen) have 1 valence electron. H hydrogen

Alkaline Earth Metals (Column 2) – also reactive – also do not occur in nature alone (fireworks) 2 valence electrons. Li Na K Rb

Transition Elements (Columns 3 – 12) stable metals – occur in natural state. usually have 2 – 3 valence electrons to give up to form bonds.

Mixed groups Boron group (13) – mixed with both metals and non- metals. 3 valence electrons

Mixed groups cont. Carbon group (14) – mixed with both metals and non- metals. 4 valence electrons

Mixed groups cont. Nitrogen group (15) – mixed – tend to share to form covalent bonds – fertilizers. 5 valence electrons

Mixed groups cont. Oxygen group (16) – mixed 6 Valence electrons

Halogens (17 – all nonmetal) – very reactive in their element form. If combined with a metal forms salt. Many are diatomic (F,Cl,Br) Br – only nonmetal liquid. 7 valence electrons

Noble Gases (18)– Most stable because outer layer is full. No known natural compounds. Helium gas, neon / argon in neon lights, argon / krypton in electric light-bulbs, used to produce lasers 8 valence electrons (full shell)

Other Groups Iron Triad – Iron, Cobalt, and Nickel – create steel and other metal mixtures.

Other groups cont. Coinage group – Copper, Silver, and Gold – stable and malleable and found in nature – used to make coins.

Other groups cont. Coating metals / Zinc group – Zinc, Cadmium, and Mercury – used to coat or plate other metals – Mercury only liquid metal (cadmium and mercury used in batteries.)

Other groups cont. Lanthanide series – elements 58 – 71 Actinide series – elements 90 – 103 Transuranium – all elements over 92

Allotropes (recall isotopes) – materials made of the same element that have different molecular structure. Diamonds Graphite