Atoms and molecules are the building blocks of everything around...
Chemistry102 views·Updated 4 Sept 2026·2 pagesUnderstanding Atoms and Molecules: A Beginner's Guide
Gavenpreet @gavenpreet_erow
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Atoms, Molecules and Compounds
Atoms are the tiniest particles that cannot be broken down further. They never join with other atoms of the same type and are found in elements like Hydrogen (H). Each element contains only its own type of atoms.
When atoms of the same element join together, they create a molecule. For example, oxygen exists as O₂, meaning two oxygen atoms have joined together. Helium, however, remains as single atoms and doesn't form molecules.
A compound forms when atoms of different elements join together through chemical bonds. Water (H₂O) is a compound made of one oxygen atom bonded with two hydrogen atoms.
Remember this! Everything can be classified as either an element (single type of atom), a compound (different atoms chemically bonded), or a mixture (different elements or compounds mixed together but not chemically bonded).
2
of 2
Atomic Structure
Atoms may be tiny, but they have their own structure! Each atom has a central nucleus surrounded by even smaller particles called electrons. The nucleus contains protons (positive charge) and neutrons (neutral charge), while electrons (negative charge) orbit around it.
The atomic number tells you how many protons an atom has. Since atoms are normally neutral, the number of electrons equals the number of protons. For example, oxygen has 8 protons, so it also has 8 electrons.
The atomic mass is the total number of protons and neutrons in an atom. For oxygen, the atomic number is 8 (protons), and the atomic mass is 16 (8 protons + 8 neutrons).
Quick tip: On the periodic table, you'll see the atomic number as a smaller number and the atomic mass as a larger number. For example, sodium (Na) has an atomic number of 11 and an atomic mass of approximately 23.
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Chemistry102 views·Updated 4 Sept 2026·2 pagesUnderstanding Atoms and Molecules: A Beginner's Guide
Gavenpreet @gavenpreet_erow
Atoms and molecules are the building blocks of everything around us. These tiny particles form elements, compounds, and mixtures that make up our world. Understanding their structure helps us learn how different substances behave and interact.
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Atoms, Molecules and Compounds
Atoms are the tiniest particles that cannot be broken down further. They never join with other atoms of the same type and are found in elements like Hydrogen (H). Each element contains only its own type of atoms.
When atoms of the same element join together, they create a molecule. For example, oxygen exists as O₂, meaning two oxygen atoms have joined together. Helium, however, remains as single atoms and doesn't form molecules.
A compound forms when atoms of different elements join together through chemical bonds. Water (H₂O) is a compound made of one oxygen atom bonded with two hydrogen atoms.
Remember this! Everything can be classified as either an element (single type of atom), a compound (different atoms chemically bonded), or a mixture (different elements or compounds mixed together but not chemically bonded).
2
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Atomic Structure
Atoms may be tiny, but they have their own structure! Each atom has a central nucleus surrounded by even smaller particles called electrons. The nucleus contains protons (positive charge) and neutrons (neutral charge), while electrons (negative charge) orbit around it.
The atomic number tells you how many protons an atom has. Since atoms are normally neutral, the number of electrons equals the number of protons. For example, oxygen has 8 protons, so it also has 8 electrons.
The atomic mass is the total number of protons and neutrons in an atom. For oxygen, the atomic number is 8 (protons), and the atomic mass is 16 (8 protons + 8 neutrons).
Quick tip: On the periodic table, you'll see the atomic number as a smaller number and the atomic mass as a larger number. For example, sodium (Na) has an atomic number of 11 and an atomic mass of approximately 23.
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