Unit 1 Chemistry

Review of Basic Chemistry

namechargesymbolmasslocation proton electron neutron + - o p+p+ e-e- nono 1 amu 1/1837 amu nucleus orbiting the nucleus 1 amu = 1.67 x g

A: Subatomic Particles Atoms are composed of protons, electrons, and neutrons. Electrons carry a negative charge and move around the nucleus. The nucleus is made up of positively charged protons, and neutrons, which have no electrical charge.

Size of 1 Atom: An atom is around 0.1 nanometer, or 100 picometers.

B: Structure of Atoms In a neutral atom, the number of protons (atomic number) = the number of electrons. The mass number = # protons + # neutrons. Each electron orbital can hold a certain number of electrons: 1 st orbital can hold only 2 e - (inner most) 2 nd orbital can hold only 8 e - 3 rd orbital can hold only 8 e - 4 th orbital can hold only 18 e -

Atomic structure of a fluorine atom:

Electrons do NOT orbit the nucleus like planets orbit the sun Rather, they occupy “areas of probability” around the nucleus

Element Number of Neutrons Number of Electrons Number of Protons Mass Number uranium sodium 6 6 carbon fluorine sulphur silver

How many electrons does a sodium atom have in its outer orbit? How many electrons does carbon have in its outer orbit? How many neutrons does a nickel atom have? How many electrons does hydrogen have? How many electrons does helium have in its outer orbit? Does oxygen have a complete outer electron orbit? one four 31 one two No – 6 electrons

The Periodic Table

Constructing a “Periodic Table” look at each animal and make brief notes about its appearance when we have seen all of the animals, you will arrange them into logical groups based on ?

tiger 1 m eland 1 m zebra 1 m wild horse 1 m

coyote 1 m impala 1 m jackal 1 m wildcat 0.3 m

lynx 1 m kudu wild ass 1 m

timberwolf 1 m gazelle leopard 1 m

now put these animals into two logical groups now divide the two groups each into two subgroups then organize them in the same pattern within each group

wildcat lynx leopard tiger wild ass zebra wild horse gazelle impala kudu eland jackal coyote wolf we can arrange them into groups by appearance and then within groups, by size

wildcat lynx leopard tiger wild ass zebra wild horse gazelle impala kudu eland jackal coyote timberwolf wildcat lynx leopard tiger jackal coyote timberwolf wild ass zebra wild horse gazelle impala kudu eland carnivoresherbivores take lifegive up life Not all herbivores are equal, some give up life more easily Not all carnivores are equal, some take life more easily

now let’s relate this to the real Periodic Table of Elements

C: The Periodic Table The periodic table is made of three types of elements; 1. metals (give up electrons) 2. non-metals (take electrons) 3. metalloids (bit of both)  boron, silicon, germanium, arsenic, antimony, tellurium, polonium

A chemical group/family is a vertical column of elements that have similar physical and chemical properties. Column 1: alkali metals Column 2: alkaline earth metals Column 3-11: transition metals Column 17: halogens Column 18: noble gases/inert gases Two Rows at Bottom: rare earth metals On the periodic table there are 18 vertical groups.

based only on atomic properties the Periodic Table would look like this!! for convenience, we pull out the rare earths so the Periodic Table looks like what we see

Periods Periods are horizontal rows of elements. The first period (row) contains 2 elements. The second period (row) contains 8 elements etc. The properties of an element gradually change across a period. The size of an atom gets smaller as you move across a period.

Valence electrons: Electrons that occupy the outermost orbital are responsible for the chemical behavior of the element. sodium atom

D: Lewis Diagrams Lewis diagrams show the number of electrons in the outermost orbit only. R Take out a piece of paper and make Lewis diagrams for B, Be, C, Cl, F, H, He, Li, Mg, N, Na, O, P, S