### Present Remotely

Send the link below via email or IM

• Invited audience members will follow you as you navigate and present
• People invited to a presentation do not need a Prezi account
• This link expires 10 minutes after you close the presentation

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

# Atoms, Elements, Compounds

No description
by

## Maria Taydem

on 20 January 2015

Report abuse

#### Transcript of Atoms, Elements, Compounds

Lose 1 e- to form +1 cations
Lose 2 e-'s to form +2 cations
Gain 2 e-'s to form -2 anions
Gain 1 e- to form -1 anions
Stable - neither gains nor loses; neighboring groups want to be like them.
Various charges; you'll have to memorize!
Add one proton and one electron as you move from element to element.
positive charge;
found in the nucleus
negative charge; found outside the nucleus
An element is defined by the number of protons.
An element can have multiple isotopes.
# protons = # electrons for atoms
When # protons and # electrons are different: ions
more e- than p+ : anion (negative charge)
more p+ than e-: cation (positive charge)
same # protons, different # neutrons
Ionic compounds - electrons are transferred from one atom to another, creating ions. Occur between metals (cation) and non-metals (anion) Charges must total 0.

Covalent compounds - electrons are shared between atoms. Occur between 2 non-metals
A

Z
X
Atomic symbol
mass number
(protons + neutrons)
atomic number
(protons)
# protons
atomic mass
Atomic Mass of Si: weighted average of each isotope
= .9223 (27.976928) + .0467(28.976496) + .0310(29.973772)
= 28.0853
Thallium has two stable isotopes, Tl 203 and Tl 205. Knowing that the atomic weight of thallium is 204.4, which isotope is the more abundant of the two?
Use the table above to calculate the atomic mass for boron. Do you get the mass shown in the periodic table?
Atomic masses are used to calculate molecular mass:
12.011 amu + 2(16.00 amu) = 48.011 amu
C O CO
2
Calculate the molecular mass for:
Groups
Periods
Full transcript