Remember the characteristics of each atom?
Proton , , mass = 1, charge = +1, located in the nucleus
Neutron, ,mass is >1, charge = 0, located in the nucleus
Electron, , does no = to 0, charge = -1, located around the nucleus
The # of protons = # of electrons
Atomic number (Z): number of protons found in a nucleus
- the atomic number = the number of protons = the number of electrons
Ions: atoms able to gain or lose electrons
- # of protons - # of electrons = the charge
Electrically charged atoms:
- negative charged ion are electrons added to a neutral atom
- positive charged ion are electrons removed from a neutral atom
Mass number: the total number of protons and neutrons
- atomic mass = # of protons + # of neutrons
- number of neutrons = mass # - atomic #
- mass # = # of protons + # of neutrons
Atomic mass: the average of an isotope
Isotopes: same number of protons and electrons but different number of neutrons
Natural Mixtures of Isotopes:
We have an element with 4 naturally occuring isotopes. Here are their atomic masses and percent abundance: a = 46 (25%), b = 47 (50%), c = 48 (15%), and d = 49 (10%). Find the atomic mass!
46 x 25% = 11.5
47 x 50% = 23.5
48 x 15% = 7.2
49 x 10% = 4.9
11.5 + 23.5 + 7.2 + 4.9 = 47.1 atomic mass units
You try some with the link below!
http://www.chem4kids.com/activities.html
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