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Atomic Structure Exploration

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Atomic Structure Exploration

Help the crew of a tiny research submarine identify atoms in a sample. Use the information in each question. Assume atoms are neutral unless told otherwise.

Meet the particles

An atom has a tiny central nucleus and electrons outside it. Protons have a charge of +1, neutrons have no charge, and electrons have a charge of −1. Almost all of an atom’s mass is in its nucleus.

Decode the atom

Use the particle information in each question to answer Questions 1–3.

1.Which particle in a carbon atom has a negative charge?

Proton
Neutron
Electron
Nucleus

2.A carbon atom has 6 protons. Where are these protons located?

3.A neutral carbon atom has 6 protons and 6 electrons. Explain how its charged particles balance.

Atomic number and mass number

The atomic number tells you the number of protons. For a neutral atom, the number of electrons equals the number of protons. The mass number is the total number of protons and neutrons.

4.A neutral sodium atom has 11 protons and 12 neutrons. Find its atomic number, mass number and number of electrons.

5.A neutral atom has atomic number 8 and mass number 16. How many protons, neutrons and electrons does it have?

6.Complete the particle count table. Each atom is neutral.

Atom

Protons

Neutrons

Electrons

Magnesium (atomic number 12, mass number 24)

Oxygen (atomic number 8, mass number 16)

Isotopes and models

Isotopes are atoms of the same element that have different numbers of neutrons. They have the same number of protons, so they have the same atomic number.

7.Carbon-12 and carbon-14 are both carbon atoms. Carbon-12 has 6 neutrons and carbon-14 has 8 neutrons. What makes them isotopes of the same element?

8.True or false: Changing the number of neutrons in an atom changes its atomic number. Correct the statement if it is false.

TrueFalse

9.A student says, “Electrons are inside the nucleus because they are part of the atom.” Explain what is wrong with this claim and describe where electrons are found in the simple atomic model.

10.Sketch a simple atomic model for a neutral lithium-7 atom. Include and label its nucleus, protons, neutrons, electrons and electron shells. Lithium has atomic number 3.