Structure of the Atom study guide

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Structure of the Atom study guide

Structure of the Atom

Subatomic particles are smaller than the atom
The three main subatomic particles are the proton, neutron, and the electron

Nucleus
Nucleus also called the core contains 99.9% of the mass of the atom, Contains protons and neutrons, Has a positive charge

Protons
Positively charged particle, They are identical in every element, Mass is 1 atomic mass unit (amu)

Neutrons
Have no charge, All neutrons are identical in every element, Mass 1 amu, Number of neutrons may vary from atom to atom

Atomic number

The number of protons in the nucleus determines the atomic number of the element
Isotopes
Atoms of the same element will have the same number of protons, but can have different numbers of neutrons

Mass Number and Atomic Mass

The mass number is the sum of the protons and neutrons
Used to distinguish one isotope from another
Atomic mass is the average mass of all the isotopes of an element

The Electrons
Electrons whirl around the nucleus, The mass is smaller than a proton or neutron, Have a negative charge, Spin around in energy levels billions of times a second! They move so fast that the space they spin in sometimes is referred to as an electron cloud
Each energy level can hold a certain number of electrons
the 1st 2 electrons
the 2nd 8 electrons
the 3rd 18 electrons
the 4th 32 electrons
The further away from the nucleus an electron is, the more energy it has, The number of electrons an atom has determines its chemical properties

Drawing Atoms

Find the number of protons, neutrons and electrons.
Draw a circle and label a P= and N= next to the equal signs write in the # of protons and neutrons
Draw your “shells” and place an e- for each electron, remember 2,8,18, 32

Quarks
Protons and neutrons are made of smaller particles called quarks, 3 quarks combine to form protons and neutrons, The six types of quarks are called Up, Down, Charm, Strange, Top, Bottom

The Electromagnetic Force

Can either attract or repel forces, Positive to negative is a force of attraction, Positive to positive is a force of repulsion, Keeps the electrons spinning around the nucleus

The Strong Force

Glues the protons together to form the nucleus, Cancels out the proton to proton positive charge repelling, The greatest of the four forces, but has a small range

The Weak Force

The key to the power of the sun, Responsible for radioactive decay

Gravity

The weakest force, Force of attraction between objects, Its role in the atom is not fully understood

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