Science: Atoms Elements and the Periodic Table Worksheet

Question 1

Name the three main subatomic particles found in atoms and give the charge of each one.

Accepted Answer

The three main subatomic particles are protons, neutrons, and electrons. Protons have a positive charge, neutrons have no charge, and electrons have a negative charge.

Question 2

Where are protons, neutrons, and electrons located in an atom?

Accepted Answer

Protons and neutrons are located in the nucleus at the center of the atom. Electrons are found outside the nucleus in the electron cloud.

Question 3

An atom has 11 protons. What element is it, and how do you know?

Accepted Answer

The element is sodium. I know this because the number of protons is the atomic number, and atomic number 11 belongs to sodium.

Question 4

What does the atomic number of an element tell you?

Accepted Answer

The atomic number tells how many protons are in the nucleus of an atom. In a neutral atom, it also tells how many electrons the atom has.

Question 5

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

Accepted Answer

A neutral oxygen atom has 8 protons, 8 neutrons, and 8 electrons. The atomic number gives 8 protons, the neutral atom has 8 electrons, and 16 minus 8 equals 8 neutrons.

Question 6

Explain the difference between an atom and an element.

Accepted Answer

An atom is a tiny particle that makes up matter. An element is a pure substance made of only one kind of atom.

Question 7

What is a molecule, and how is it different from a single atom?

Accepted Answer

A molecule is made of two or more atoms chemically joined together. A single atom is just one particle of an element.

Question 8

Why is the periodic table useful to scientists and students?

Accepted Answer

The periodic table is useful because it organizes elements by their properties and atomic numbers. It helps scientists and students compare elements and predict how they may behave.

Question 9

How are elements arranged across the periodic table?

Accepted Answer

Elements are arranged by increasing atomic number from left to right and top to bottom. Elements with similar properties are placed in the same columns.

Question 10

What is the difference between a period and a group on the periodic table?

Accepted Answer

A period is a horizontal row on the periodic table. A group is a vertical column, and elements in the same group often have similar properties.

Question 11

Elements in the same group often behave in similar ways. Give one reason why.

Accepted Answer

Elements in the same group often behave in similar ways because they have the same number of valence electrons. Valence electrons strongly affect how atoms react with other atoms.

Question 12

Classify each element as a metal, nonmetal, or metalloid: iron, oxygen, silicon.

Accepted Answer

Iron is a metal, oxygen is a nonmetal, and silicon is a metalloid.

Question 13

A neutral atom has 17 electrons. What is its atomic number, and what element is it?

Accepted Answer

Its atomic number is 17, and the element is chlorine. In a neutral atom, the number of electrons equals the number of protons, which equals the atomic number.

Question 14

Compare the atoms of carbon and carbon-14. How are they similar and how are they different?

Accepted Answer

Both atoms are carbon, so they have the same number of protons. Carbon-14 has more neutrons than a common carbon atom, so it has a different mass number.

Question 15

A student says that all squares on the periodic table represent compounds. Explain why this statement is incorrect.

Accepted Answer

This statement is incorrect because each square on the periodic table represents an element, not a compound. A compound is made when atoms of different elements chemically combine.

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Science: Atoms Elements and the Periodic Table

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