1. Atomic Radius and Bright Line Spectrum

2. Atomic Radius
The atomic radius of an element is defined as half the distance between two bonded atoms of the same element.

3. Atomic Radius
As you move left to right across the periodic table, the atomic radii of the elements decreases.
This is because the nuclei of these elements pick up more protons, while the energies of the electrons stays the same. Since the nucleus can pull harder but the electrons have the same energy, the electrons get pulled closer to the nucleus.
Decreases

4. Atomic Radius As you move down a group, the atomic radius increases.
That’s because the electrons are in higher energy levels, which puts them in bigger orbitals.
Increases

5. Brain Break: Intervals
10 Squats
Run in Place for 15 sec.
10 Lunges
Jump rope for 15 sec.
30 punches
Jumping jacks for 15 sec.

6. Bright Line Spectrum

7. Electrons can move between orbitals
Electrons can move between orbitals! Electrons in the outer orbitals have more energy. Electrons in inner orbitals have less energy.

8. S-orbital (1st orbital) P-orbital (2st orbital)
Atoms are stable when the electrons are in the orbitals with the lowest possible energies – called the ground state.
S-orbital (1st orbital)
holds 2 electrons
P-orbital (2st orbital)
Holds up to 8 electrons,
But oxygen only has 6

9. Atoms are excited when the electrons are in the orbitals with the higher energies – called the excited state.
S-orbital (1st orbital)
holds 2 electrons,
but in this excited state, only has 1!
P-orbital (2st orbital)
Holds up to 8 electrons,
Now it has 7

10. When electrons move from an excited state to a ground state, they will release light! We can use these bands of light to determine what element is present.
S-orbital (1st orbital)
holds 2 electrons,
but in this excited state, only has 1!
P-orbital (2st orbital)
Holds up to 8 electrons,
Now it has 7

11. Electromagnetic Spectrum

12. Visible Light Visible Light is also called white light.
All the colors of the rainbow are present in white light.

13. Bright Line Spectrum
When elements are exposed to electromagnetic waves, they will emit light in certain patterns, these are called bright line patterns.
Scientists have already tested all the elements on the periodic table, and each one had a unique bright line pattern.
Scientists can use these to identify what elements make up stars and planets in our universe.
Red light has the longest wavelength, and therefore the least amount of energy. On the other end, violet light has the shortest wavelength and therefore the most amount of energy.

14. Bright Line Patterns