This negatively charged particle is found in the electron cloud.
Electron
You find an element box on the periodic table with a big "He". What element are you looking at?
Helium
A neutral atom has 10 protons. How many electrons does it have?
An atom has 8 electrons. How should they be arranged in the shells?
2, 6
Carbon-12 and Carbon-14 are both carbon. What must they have in common?
The same number of protons
This positively charged particle is found in the nucleus.
Proton
You need to find an atom with exactly 6 protons. Which number do you search for on the periodic table: the atomic number or the atomic mass?
Atomic number
An atom has 9 protons and 10 neutrons. What is its mass number?
19
A student draws a Bohr model and puts 3 electrons in the first (innermost) shell. What mistake did they make?
2, 6
Carbon-13 has 6 protons. How many neutrons does it have?
7
This neutral particle is found in the nucleus.
Neutron
An element has an atomic number of 17. Use the periodic table to identify it.
Chlorine (Cl)
An atom has a mass number of 31 and 15 protons. How many neutrons?
16
A student draws a Bohr model and puts 3 electrons in the first (innermost) shell. What mistake did they make?
The first shell can only hold a maximum of 2 electrons
Two atoms both have 17 protons. One has 18 neutrons and the other has 20. What is different about them?
They are different isotopes of chlorine.
The nucleus contains these two subatomic particles, while this region contains electrons. (TWO ANSWERS)
Nucleus; electron cloud
Which number tells you the number of electrons?

19
An atom has 13 protons, 14 neutrons, and 13 electrons. Identify the element and mass number.
Aluminum, mass number 27
You need to draw a Bohr model for Neon (10 electrons). How many total electron shells will you need to draw?
2 shells (2 in the first, 8 in the second)
A scientist tests two atoms: Atom X has 17 protons and 18 neutrons. Atom Y has 17 protons and 20 neutrons. Write the isotope symbol/name for Atom Y.
Chlorine-37
Explain how the three subatomic particles differ in their basic role in an atom.
Protons: Identifies the element
Neutrons: Contributes to mass
Electrons: Determines charge of atom
A mystery element has an atomic number of 20. Identify its name, symbol, and number of protons.
Calcium, Ca, 20 protons
²⁷₁₃Al is shown on a test. How many protons, neutrons, and electrons does a neutral atom have?
13 protons, 14 neutrons, 13 electrons
You are drawing a Bohr model for Carbon (6 electrons total). How many electrons should be in the second shell?
4 electrons (2 in the first shell, 4 in the second)
Atom A has 8 protons and 8 neutrons. Atom B has 8 protons and 10 neutrons. Which one has greater mass, and why?
Atom B, because it has 2 more neutrons.