Atoms

An atom is the basic unit of matter, consisting of a nucleus containing protons and neutrons, surrounded by electrons in shells. Atoms are the building blocks of all substances and are incredibly small, with a diameter on the order of a few angstroms.

Structure of an Atom

The nucleus of an atom contains protons, which have a positive charge, and neutrons, which have no charge. The electrons, which have a negative charge, orbit the nucleus in specific energy levels or shells.

Subatomic Particles

• Protons: Positively charged particles found in the nucleus.
• Neutrons: Neutral particles found in the nucleus.
• Electrons: Negatively charged particles found in shells surrounding the nucleus.

Atomic Number and Mass Number

The atomic number of an atom is the number of protons in its nucleus. The mass number is the sum of the protons and neutrons in the nucleus.

Study Tips

1. Memorize the first 20 elements of the periodic table and their symbols.
2. Understand the concept of atomic number and mass number.
3. Practice drawing the structure of an atom, including the arrangement of protons, neutrons, and electrons.
4. Learn about isotopes and their significance.

[Atoms] Related Worksheets and Study Guides:

• Introduction to matterScience • Sixth Grade
• Atoms and Chemical BondingChemistry • High School
• Properties of atomsScience • Eighth Grade