# Do the pre-assessment on a separate sheet of paper.

## Presentation on theme: "Do the pre-assessment on a separate sheet of paper."— Presentation transcript:

Do the pre-assessment on a separate sheet of paper.
Structure of Atoms Do the pre-assessment on a separate sheet of paper.

Atom: the smallest unit of matter that retains the identity of an element

Atoms 2 regions: 1) Nucleus: center of the atom- contains most the mass 2) Electron shells-region surrounding nucleus-contains most the space of atom Nucleus Electron shells

3 subatomic particles 1) Protons: + charged particles
2) Neutrons: un-charged particles 3) Electrons: - charged particles In nucleus In electron shells

Atomic Anatomy Proton p+ 1 amu + nucleus neutron n0 Electron e-
What they look like The guts of an atom “Subatomic Particles” # e- = # p+ (for neutral atoms) Particle (symbol) Mass Charge Location Proton p+ 1 amu + nucleus neutron n0 Electron e- amu - Electron shells + e- + e- Nucleus

O Name Atomic #: # of protons And same # of electrons Symbol:
8 O Oxygen 15.999 Symbol: 1st letter always capital 2nd letter lowercase Name Average Atomic Mass: # of p+ + # n0 # n0 = mass – atomic # (Hint: round mass)

Practice finding # e-, p+ and n0
Element Protons Electrons Neutrons 7 N Nitrogen 14.01 14-7 = 7 7 7 15 P Phosphorus 30.97 31-15 = 16 15 15 11 Na Sodium 22.99 23-11 = 12 11 11

So how do we draw the atoms?
Ex: Li- Three protons (atomic number.) 3 Li Lithium 6.941 P+ P+ P+

Four neutrons. (mass – atomic number.)
3 Li Lithium 6.941 o n0 o o n0 P+ n0 P+ o P+ n0

Three electrons, In two electron shells.
3 Li Lithium 6.941 e- e- o n0 o o n0 P+ n0 e- P+ P+ n0

Shell # # of e- 1 2 Go in as a pair 8 1 in each of 4 corners then pair up 3 8 (sort of-more to come) 4

Na To check your understanding, draw an atom of Sodium (Na). 11 Sodium
22.990

Na 11 p+ 12 n0 Bohr Model of a sodium atom 11 Sodium 22.990 e- e- e-
For bigger atoms, it is easier to write the number of protons and neutrons in the nucleus, than draw each of them out. You should always draw each electron. e- e- 11 p+ 12 n0 11 Na Sodium 22.990 e- e- e- e- e- e- e- e- e-

What do I need to Know? You must be able to draw elements 1-36
Everyone should know the name/chemical symbol for elements 1-36 plus gold, sliver, mercury, iodine, and lead

Do Now: 10/8 Compare the relative size, location and mass of the three sub atomic particles. Draw a Bohr model for an atom of calcium.

More Practice 6 5 5 20 20 20 2 2 2 B Ca He 11-5 = 40-20 = 4-2 =
Element Protons Electrons Neutrons 5 B Boron 10.81 11-5 = 6 5 5 20 Ca Calcium 40.08 40-20 = 20 20 20 2 He Helium 4.00 4-2 = 2 2 2