The creators of the table

1. Things to know, symbol, atomic number, atomic weight, stairstep, s,p,d,fareas. Period, group, column family

2. The creators of the table • Dobereiner arranged by property into triads, relying heavily on atomic mass • Newland noticed that properties tend to repeat every 8, called them octets ( we still use the octet rule today, which says properties repeat in a recognizable pattern, see the table we have

3. The first actual table • Mendeleev is our main guy! • He put atoms together by characteristics, arranged them all in a way they are easier to learn. He focused • 1st on characteristic, • 2nd on atomic mass • Left places for atoms not yet found • Predicted element characteristic • He was right in Many cases!!

4. It wasn’t until after all this that atomic number was discovered, and there wasvery little rearranging needed • Go Mendeleev!!!

5. Periodic Law- know it, don’t break it • States that properties of elements reoccur in a given pattern. • When elements are arranged in their atomic number order, those patterns can be seen.

6. Group 1- alkali metals • 1st row of the periodic table, these are very reactive metals, they are not found in nature alone. • Soft, silvery, not dense • Used in human chemistry, • Li is a medicine • More reactive farther down the list

7. Group 2 alkaline earth metals • Still soft, silvery metals, but harder, denser and stronger than group 1 • Too reactive to find alone in nature, but less explosive than group 1 • Called earth metals because found in the soil, in jewels (Be), in the ocean ( Mg ), in rocks (Ca) • Great for fireworks and flares ( Sr, Ba)

8. Hydrogen and Helium • Group 1 and group 2, but not included in alkali and alkaline metals! • Why? Because they are gases! • Colorless, odorless gases, H is very reactive, He is totally nonreactive ( full valance shell) • Hydrogen in the air, Helium, in the ground in Texas

9. Transition metals • Also called D block metals, all have s2 in common • These are the classic metals • Dense • Solids ( not mercury) • Lustrous • Found as elements in nature • Malleable ( bendable) • Ductile ( turn into wires) • Conduct and heat and electricity

10. What do we do with metals? • Build stuff like houses, buildings, cars, cans, Industry!!!( Iron and others) tools weapons • Wiring for EVERYTHING! ( copper) • Need trace amounts to carry oxygen, make your muscles and nerves work • Jewelry gold and silver, platinum, titanium • Money silver and gold, nickel, zinc and copper • Light bulbs ( tungsten)

11. Metalloids/ semi metals • Groups 1-12, and parts of 13 are metals • Groups 18,17, and parts of 15,14,are nonmetals • in between, along the stair step, are 7 metalloids, so named because they have characteristics of metals and nonmetals. • They include, B, Si, Ge, As, Sb, Te, Po • Solids, but they are brittle, not all shiny, but some are, and they are semi conductor ( conduct, but slowly)

12. Uses for metalloids • Semi conductors in computers, cell phones, calculators, PDA’s etc. • silicon- Implants, insulation, caulk, • Arsenic- poison white crystal solid, looks like sugar, • Useful in rat poison, natural substance

13. P block nonmetals • Elements in groups 13-16 • Some solids,liquids and gases • Most are reactive, many are found in organic compounds ( of living things) • Carbon is the backbone of living things, oxygen is not only in compounds but elemental in all living things, N and P and S are found throughout living organisms. • They vary in color from black (C) • S is yellow, P can be red or yellow , N and O are colorless odorless gases.

14. Halogens- group 17 • Most reactive nonmetals, they are not in nature as elements. • All are poisonous as elements, but very useful in compounds • F- keeps your mouth clean, found in water • Cl- cleaner for pools, concrete, industry, is a heavy green gas • Bromine is a red liquid, also very heavy, iodine is a purple crystalline solid, both useful for killing bacteria and fungi in compounds, poisonous to humans in elemental form • Useful in photography, insecticides and lights

15. Nobel gases • Group 18( see red column) • All gases • Full valance shell, so do not react • Useful to pack reactive substances for shipping • Very high burn point so used in welding • Also useful for lights (Neon lights !)

16. Lanthanides and actinides • The 4F’s are Lanthanides – a group of very similar very dense metals. Not used for too much, they are so similar they are hard to separate • The 5f’s are actinides, only the first four are natural, the rest are man made, all are radioactive. Useful for treating cancers and diseases, tracing elements through natural systems ( water ways and rivers) Used for nuclear energy and bombs.

17. Trends of the periodic table • These are certain characteristics that show a definite pattern across the periodic table. It is useful to help figure which atoms do what, which atoms are useful in certain situations • 1st atomic radius! Size of the atom. • As you go down the PT, the atoms get larger • ( should make sense, they have more shells) • As you go across, they get smaller • I know that is weird, but more protons in the same shell pull them in closer

19. Trend 2 Ionic radius • An ion is an atom that has gained or lost an electron • If an atom has 4 or less valance electrons, it loses them ( groups 1-14) • Makes the atom smaller – called a cation • Left of metalloids get smaller • When they lose electrons, they become positively charged. ( have more protons than electrons) • Atoms with more than 4 valance electrons gain electrons • Makes the atoms larger, call them anions • Have a negative charge

20. Some examples • sodium metal Na wants to lose one electron. • Mrs. Holtmeyer leaves it out. There is oxygen in the air. O wants to… gain 2 because it already has 6! • 2 Na and O get close, and Na gives electrons to the O!!! Na+ and O-, and opposites attract, so they are now stuck together in a compound called Na2O. CaO

21. Trend 3 Ionization energy • Energy to lose electrons • The easier it is, the less energy it takes • Less energy on left, more on the right • More energy on the top, less on the bottom

22. trend 4! Electron affinity • The opposite of ionization energy, this is energy to gain electrons • More energy on the left, less on the right • Less energy on the top, more on bottom • If electrons are VERY easy to add, the # is negative! • For instance if you had an electron affinity of –567 kJ. This means energy leaves the reaction

23. Trend 5 Electronegativity • Much like e. affinity, this is the ability of atoms to hold onto BONDED e-. • Very useful, numbers 0-4 have been assigned to represent, with 4 being the most electronegative. F is a 4. Trend follows just like ionization, Flourine is highest and Francinium is lowest