Day 23 – Daily Starter What do you remember about the structure/ make-up of an atom? (“IDK” is not an answer)

Today’s Topic: Atomic Structure Unit 2 Chemistry Review Today’s Topic: Atomic Structure

Niels Bohr (1913) Bright-Line Spectrum tried to explain presence of specific colors in hydrogen’s spectrum

Niels Bohr (1913) Energy Levels Planetary Model electrons can only exist in specific energy states Planetary Model Electrons move in circular orbits with specific energy levels

Erwin Schrödinger (1926) Quantum mechanics Electron cloud model electrons can only exist in specified energy states Electron cloud model orbital: region around the nucleus where e- are likely to be found

Electron Cloud Model (orbital) Erwin Schrödinger (1926) Electron Cloud Model (orbital) dots represent probability of finding an e- not actual electrons

James Chadwick (1932) Discovered neutrons Joliot-Curie Experiments neutral particles in the nucleus of an atom Joliot-Curie Experiments based his theory on their experimental evidence

revision of Rutherford’s Nuclear Model James Chadwick (1932) Neutron Model revision of Rutherford’s Nuclear Model

II. Electron Cloud Model Orbital Energy Levels Bohr Model Diagrams

A. Orbital Region where there is 90% probability of finding an electron. Can’t pinpoint the location of an electron. Density of dots represents degree of probability.

A. Orbital Orbitals have different shapes.

B. Energy Levels Electrons can only exist at certain energy levels. Low energy levels are close to the nucleus. Each energy level (n) can hold 2n2 electrons.

C. Bohr Model Diagrams Simplified energy levels using Bohr’s idea of circular orbits. Can replace with: 3p 4n Lithium Atomic #: 3 Mass: 7 # of p: 3 # of e: 3 # of n: 4 e- e- p n Maximum e- Level 1 2e- Level 2 8e- Level 3 18e- Level 4 32e- e-

C. Bohr Model Activity Get with your assigned unit partner Choose a number between 1 & 18. Find your element by the atomic number you picked. Draw a Bohr Model diagram for your element. Refer to the mass listed on the table and subtract the atomic # to find the # of neutrons. Abbreviate the # of ‘p’ and ‘n’ in the nucleus. Have your partner check your drawing. Repeat with 2 new elements (each partner draws 3)

In Class work – Show before you Go The Atoms Family Atomic Math Challenge A Review of the Periodic Table 6 C Carbon 12 Atomic number = 6 Symbol = C Name = Carbon Average atomic Mass = 12