Question

activity a: subatomic particles
get the gizmo ready:

• use the arrows to create an atom with two protons, two neutrons, and two electrons.
• turn on show element name

question: what are the properties of protons, neutrons, and electrons?

1. observe: turn on show element symbol and element notation. three numbers surround the element symbol: the mass number (a), electrical charge (no number is displayed if the atom is neutral), and the atomic number (z).
2. investigate: watch how the numbers change as you add or remove particles.

a. which number is equal to the number of protons in the atom?
b. how can you calculate the number of neutrons (n) in an atom?
c. which particle (proton, neutron, or electron) has a positive charge? negative charge? no charge at all?

Explanation:

Step1: Recall atomic number definition

The atomic number ($Z$) of an atom is equal to the number of protons in the nucleus of that atom.

Step2: Recall mass - number formula

The mass number ($A$) of an atom is the sum of the number of protons and neutrons. So, the number of neutrons ($N$) can be calculated as $N=A - Z$.

Step3: Recall charges of sub - atomic particles

Protons have a positive charge, electrons have a negative charge, and neutrons have no charge.

Answer:

A. The atomic number ($Z$) is equal to the number of protons in the atom.
B. $N = A - Z$
C. Positive charge: proton; Negative charge: electron; No charge at all: neutron