Question

directions for #3-6:
when drawing atoms, the 1st shell is like a front row of seats in an auditorium that only has 2 seats. once those seats are filled guests must move into the 2nd row and so forth. in an auditorium, seats will not be filled unless there are enough guests. the same things happens with the energy levels, shells or orbitals. they will only be filled with as many electrons as an individual atom has.

ex) hydrogen, h
atomic # = 1 (top # in h box on the periodic table)
mass # = 1 (rounded atomic mass from the periodic table)

protons = 1 (equal to atomic #)

electrons = 1 (also equal to atomic #)

neutrons = 0 (equal to mass # - atomic #)

ex) phosphorus, p
atomic # = 15 (top # in h box on the periodic table)
mass # = 31 (rounded atomic mass from the periodic table)

protons = 15 (equal to atomic #)

electrons = 15 (also equal to atomic #)

neutrons = 16 (equal to mass # - atomic #)

1. helium, he

drawing of helium
atomic # = 2
mass # =

protons = 2

electrons =

neutrons =

Explanation:

Step1: Find Mass # of Helium

From the periodic table, the atomic mass of Helium (He) is approximately 4 (rounded). So Mass # = 4.

Step2: Determine # Electrons

Electrons is equal to Atomic #. Atomic # of He is 2, so # Electrons = 2.

Step3: Calculate # Neutrons

Neutrons = Mass # - Atomic #. Substituting values: 4 - 2 = 2. So # Neutrons = 2.

Step4: Draw Helium Atom

The 1st shell (energy level) can hold 2 electrons. Helium has 2 electrons, so both electrons are in the 1st shell. Draw a circle (nucleus) with 2 protons and 2 neutrons (from # Protons = 2 and # Neutrons = 2), and a larger circle (1st shell) with 2 electrons on it.

Answer:

• Mass # = 4
• # Electrons = 2
• # Neutrons = 2
• Drawing: A nucleus (circle) with 2 protons and 2 neutrons, and a single electron shell (circle around nucleus) with 2 electrons.