2.2 Basic Atomic Structure

Published by admin on

Atom
The smallest particle of an element that still retains the chemical properties of that element.
electrons, protons, neutrons
3 subatomic particles atoms are made of
electrons
1.Possesses negative electrical charges.
2.Are found orbiting the nucleus of an atom (the electron cloud)
3.Are 1/1837th of the mass of a single proton or neutron
protons
1.Possess a positive electrical charge.
2.Are found clumped together within the nucleus of an atom.
3.Has a mass of 1 atomic mass unit (AMU) or 1 Dalton (Named after John Dalton.)
neutrons
1. Possesses no electrical charge and are therefore referred to as neutral.
2. Are also found clumped together within the nucleus an atom.
3. Has a mass of 1 AMU or 1 Dalton.
Nuclear forces
These are short-range proton-to-neutron OR proton-to-proton OR neutron-to-neutron attractive forces that help hold together the nucleus of an atom.

These forces are greater than the repulsive same charge electrical forces exhibit by protons.

Atomic theory 1
All matter is composed of extremely small particles called “atoms”.
Atomic theory 2
Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, and other properties.
This has since been modified based on isotopes and ions.
Atomic theory 3
Atoms cannot be subdivided, created, or destroyed.
a. This has since been modified based upon current studies in quantum physics. Such examples include muons and quarks.
Atomic theory 4
Atoms of different elements combine in simple different ratios to form chemical compounds.
Atomic theory 5
In chemical reactions, atoms are combined, separated, or rearranged.
Dalton’s main flaws in the atomic theory
Atoms are not indivisible. The are divisible into several subatomic particles.
All atoms of a given element may not have identical properties as their masses may vary slightly (ie. isotopes).
Categories: Atomic Physics