Sub-atomic Particles
What are the three sub-atomic particles?
Protons, neutrons, and electrons
What happens if the number of protons equals electrons?
The atom is neutral
What is an analogy?
A comparison that helps explain something
Q1: Give the relative charge and mass on a proton, neutron, and electron.
Proton: +1, mass 1; Neutron: 0, mass 1; Electron: –1, mass 1/2000
Where are protons and neutrons found?
In the nucleus
Where are electrons found?
Orbiting outside the nucleus
If an atom were a football stadium, what would the nucleus be?
The size of a pea
Q3. Describe an analogy that helps to explain the size of a nucleus compared to its atom.
If the atom were a football stadium, the nucleus would be the size of a pea
Which particle has the smallest mass?
The electron (1/2000 of a proton’s mass)
What type of force holds the atom together?
Electrostatic attraction between nucleus and electrons
Why is that analogy useful?
It shows the nucleus is tiny compared to the atom’s size
Q5. Explain why a beryllium atom is electrically neutral.
Because it has equal numbers of protons (+4) and electrons (–4)
Q4. Draw a beryllium atom (4p, 5n, 4e).
Nucleus: 4 protons, 5 neutrons; 2 electrons in 1st shell, 2 in 2nd shell