March 5th Chem 11

Friday, March 5, 2010

Today we learned about emission spectra...

-Each element gives off a specific colour of light
- These are known as emission spectra
- they are different to each element
-one of the uses for this is to find out what kind of elements a star is composed of
- If electrons absorb energy they can be bumped to a higher level
- When they fall to a lower level they release that energy as light

Heres a video about the emission spectrum of hydrogen






Atomic Structure

- Atoms are made up of parts called subatomic particles (protons, neutrons and electrons)

here are the details of each subatomic particle:

-A proton has 1 mass, +1 charge, and is in the nucleus
-A neutron has 1 mass, neutral charge, and is in the nucleus
-A electron is 1/1850 mass, -1 charge, and is arranged in energy level around the nucleus

Atomic Number

<------------ the number at the top left corner is the atomic number

- The nymber of protons determine the type of element
Isotopes

- Changing the number of neutrons changes the isotopes of the element
- All isotopes have the same chemical properties

For example carbon 12 has a 12 protons, and 6 neutrons
but as you add another neutron, the weight increases to 13 which gives you carbon 13
the same happens with carbon 14 respectively

Here is a little video about isotopes...

Mass number
-the total number of protons and neutrons

- Symbol given is A

- Different isotopes have different masses

Let's say you're given the Isotope of 12-Ca. The mass would be 12, the atomic number would stay the same as it is given in the periodic table (6), the number of protons would be 6 (same as the atomic number) and the number of neutrons would be 6 (mass number - atomic number).

here is a video about isotopes: