atomic structure. learning goals identify and describe particles which comprise atoms. compare...

Atomic Structure

Learning Goals

Identify and describe particles which comprise atoms.

Compare atoms and contrast forces inside.

Determine subatomic particles from atomic number and mass number.

Bellringer

What is an atom?

What does an atom look like?

Body Essentials

Protein Lipids (Fat) Carbohydrate

Macromolecules that aid in human performance.To understand their functions we must understand their

structure.

Structure of the Atom

In order to understand atoms, we need to understand the idea of electric charge.

We know of two different kinds of electric charge and we call them positive and negative.

Electric charge in matter We say an object is electrically neutral

when its total electric charge is zero.

Nucleus- small dense center of the atom.protons and neutrons

Electron Cloud- outer part of atom where the electrons lie.

Inside an atom The mass of the nucleus

determines the mass of an atom!!

protons and neutrons are much larger and more massive than electrons.

In fact, a proton is 1,836 times heavier than an electron! WOW!

Proton and Neutron weigh almost the

same

Force inside atoms

Electrons are bound to the nucleus by the attractive force between electrons (-) and protons (+).

Force inside atomsWhat holds the nucleus together?

There is another force that is even stronger than the electric force.

We call it the strong nuclear force.

How are atoms of various elements different?

The atoms of different elements contain different numbers of protons in the nucleus.

Because the number of protons is so important, it is called the atomic number.

SUPER SUPER IMPORTANT!

Protons define the element! CAN’T CHANGE NUMBER OF

PROTONS!

Hydrogen ALWAYS has 1 protonHelium ALWAYS has 2 protons

Chlorine ALWAYS has 17 protons

What info can we gather from the Periodic Table?

Atomic Number =# of protons / # of electronsSymbol of element

Atomic Mass =(# of protons) + (# of neutrons)

Check for Understanding!How many protons,

neutrons, and electrons are in iron given the periodic

table?Answer:

26 protons, 26 electrons, and 30

neutrons

Calculating P, N, and E

Symbol Mass Proton Neutron Electron

B 6

24 11

Pb 207

You may need the Periodic Table to fill in this chart