 # Atomic Structure. What Is An Atom? the smallest particle of an element that retains the chemical properties of that element Can be subdivided into electrons.

## Presentation on theme: "Atomic Structure. What Is An Atom? the smallest particle of an element that retains the chemical properties of that element Can be subdivided into electrons."— Presentation transcript:

Atomic Structure

What Is An Atom? the smallest particle of an element that retains the chemical properties of that element Can be subdivided into electrons (e - ), protons (p + ) and neutrons (n 0 )

Diagram Of An Atom

Important Info About Subatomic Particles ParticleRelative Electric Charge Mass NumberRelative Mass (amu) Actual Mass (kg) Electron (e - )0.00054869.109 x 10 -31 Proton (p + )+111.0072761.673 x 10 -27 Neutron (n o )011.0086651.675 x 10 -27 1 amu = 1.660540 x 10 -27 kg 1 amu = (1/12)(mass of C-12 isotope in kg) Amu = atomic mass units

Atomic Number (Z) Tells us the number of protons in the nucleus of an atom Z

Isotopes Some atoms of the same element will have different masses. These atoms are called isotopes because they have the same number of protons, but differ in the number of neutrons. Isotopes of the same element have different mass numbers. Mass number (A) is the total number of protons and neutrons in the nucleus of an isotope

How Are Isotope Symbols Denoted?

Hyphen Notation of Isotopes Isotopes can also be denoted through hyphen notation The element symbol will be listed, following a hyphen, and then a mass number (p + + n 0 ) Ex. Hydrogen has 3 isotopes (H-1, H-2, H-3)

Hydrogen Isotopes AKA “Protium” 99.985% Abundant H-1.015% Abundant H-2 Radioactive, Prepared Artifically H-3

Sample Problems How many protons, electrons, and neutrons are there in a Cl-37 atom? How many protons, electrons, and neutrons are there in the following isotopes?

Atomic Mass What is the atomic mass listed on the periodic table under each element really measuring? This mass is a weighted average of all of the naturally occurring isotopes of an element This mass is a relative average (compared to the C-12 isotope) in atomic mass units (amu)

How To Find The Atomic Mass of Hydrogen H-1 is 99.985% abundant with an atomic mass of 1.007825 amu H-2 is.015% abundant with an atomic mass of 2.016490 amu H-3 is not counted because of the fact that it is not naturally occurring To find the weighted average: (% abundance/100)(relative atomic mass of isotope 1) + (% abundance/100)(relative atomic mass of isotope 2) + (% abundance/100)(relative atomic mass of isotope 3)… *Mass # may be substituted for the relative atomic mass when given (99.985%/100)(1.007825 amu) + (.015%/100)(2.016940 amu) = 1.0079 amu

Things To Remember… If you change the number of protons, you change the type of atom itself. If you change the number of electrons, you change the atom to an ion (charged particle). If you change the number of neutrons, you change the isotope of that element.

Download ppt "Atomic Structure. What Is An Atom? the smallest particle of an element that retains the chemical properties of that element Can be subdivided into electrons."

Similar presentations