Atoms Notes

• An Atom is the smallest particle of an element.

Electrical Charges:

• Can be Positive (+) or Negative (-).

• A positive & negative charge attracts each other, while 2 or more positive or negative charge reject each other.

• Subatomic particles: Particles that’s located INSIDE of the atom.

  -Example: Proton, Electron , Neutron

1. Proton: A positively charged subatomic particle located inside the nucleus and it defines it’s atomic number and element.

• Symbol: p+

• Charge: 1+

• Mass of 1.007 amu

  2. Neutron: A neutral subatomic particle located inside the nucleus, contributing to its mass. Families of an element has the same number of protons but different numbers of neutrons.

• Symbol: n0

• Charge: 0

• Mass of 1.008 amu

  3. Electron: A negatively charged subatomic particle located outside the nucleus. The flow of electrons through a wire creates a electric current (powering devices)

• Symbol: e-

• Charge: 1-

• Mass of 0.00055 amu

Atomic Number:

• The Number located above the element.

• Atomic Number = Number of Protons & Electrons.

Atomic Mass:

• The mass of an atoms element is rounded to the nearest WHOLE number.

• Total count of protons and neutrons in an atom’s nucleus.

Calculating the # of Neutrons:

• Number of Neutrons = Atomic Mass - Atomic Number