1. Daily Warm Up October 24, 2014 Two Questions1.
If 75.0% of the isotopes of an element have a mass of 35.0 amu and 25.0% of the isotopes have a mass of 37.0 amu, what is the atomic mass of the element?
A) 35.0 amu B) 36.0 amu
C) 35.5 amu D) 37.0 amu

2. 2.

3. Name__ October 24, 2014 R. Chem Pd __
Aim: How do electrons occupy energy levels?

4. Bohr Energy Levels:
Electrons travel in energy levels.
Energy levels are numbered, n=1 is closest to the nucleus and has the lowest energy.
Electrons completely fill the lowest energy levels first and then occupy the next energy level.

5. What do these diagrams tell us about energy levels?

6. How is this sports stadium similar to the Bohr model of the atom?

7. Ground state: electrons are in the lowest energy levels
3. Excited state: electrons absorb energy and move to higher energy levels
4. When electrons return to the ground state, they emit or release energy in the form of light and produce line spectrums.

8. √Check for understanding
Compared to a sodium atom in the ground state, a sodium atom in the excited state must have
(1) a greater number of electrons
(2) a smaller number of electrons
(3) an electron with greater energy
(4) an electron with less energy

9. √Check for understanding
What causes the emission of radiant
energy that produces characteristic
spectral lines?
(1) neutron absorption by the nucleus
(2) gamma ray emission from the nucleus
(3) movement of electrons to higher energy
levels
(4) return of electrons to lower energy levels

10. √Check for understanding
Which principal energy level change by the
electron of a hydrogen atom will cause the
greatest amount of energy to be absorbed?
(1) n = 2 to n = 4 (3) n = 4 to n = 2
(2) n = 2 to n = 5 (4) n = 5 to n = 2

11. 5. Each element has its own unique electron arrangement and therefore has a unique emission line spectrum, which is used to identify the element.

12. Emission Line Spectrum

13. Identify the two gases in the unknown mixture.

14. √Check for understanding
The characteristic bright-line spectrum of an element occurs when electrons
(1) move from lower to higher energy levels
(2) move from higher to lower energy levels
(3) are lost by a neutral atom
(4) are gained by a neutral atom