Science Flashcards: Molecule Definition

Study Notes

Molecule

A molecule is formed by two or more atoms bonded together through chemical bonds.
Represents the smallest unit of a compound.
Can consist of identical atoms (e.g., O2) or different atoms (e.g., H2O with 2 hydrogen and 1 oxygen).

Atom

Introduced by John Dalton in 1802 through atomic theory.
Atoms are indivisible and cannot be broken into smaller parts.
Atoms of an element are identical, maintaining the element's properties.

Proton

Protons are positively charged particles found in an atom's nucleus.
Atoms are incredibly small, with a single grain of sand containing more atoms than grains of sand on a beach.

Electron

Electrons are negatively charged particles that rapidly orbit the nucleus.
They are energetic and move in various directions around the nucleus.

Chemical

A chemical symbol is a shorthand representation of an element, composed of one or two letters.
The first letter is always uppercase; if a second letter is present, it is always lowercase (e.g., Na for sodium).

Chemical Formula

A chemical formula combines symbols to represent a compound (e.g., NaCl for sodium chloride).
It indicates the ratio of elements present in the compound.

Chemical Equation

Represents a chemical reaction using symbols and formulas.
Illustrates both reactants and products, similar to a mathematical equation with an "=" sign.

Coefficient

The number placed before a chemical symbol/formula in an equation.
Indicates how many molecules are involved in the reaction.

Subscript

A number positioned lower right of a chemical symbol.
Specifies the number of atoms of an element within a compound.

Atomic Number

The count of protons in an atom's nucleus determines the atomic number.
Organizes elements on the periodic table; for example, copper has an atomic number of 29.

Atomic Mass

Calculated as the sum of protons and neutrons in an atom's nucleus.

Energy Levels

Refers to specific locations where electrons are arranged around the nucleus.
The arrangement of electrons influences an element's chemical properties.

Protons and Electrons

In neutral elements, the number of protons equals the number of electrons.
Example: Oxygen, with 8 protons, also has 8 electrons.

Chemical Reaction

A process in which substances transform into different substances without matter being created or destroyed.
The mass of reactants equates to the mass of products (e.g., CH4 + 2O2 → CO2 + 2H2O).

Neutron

Neutrons are neutral particles found in an atom's nucleus (specific details not provided).

Description

Explore the concept of molecules with these science flashcards. Each card provides definitions and key insights into the structure and significance of molecules in compounds. Perfect for students looking to enhance their understanding of basic chemistry principles.

Science Flashcards: Molecule Definition

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Questions and Answers

What is a molecule?

What is the smallest part of an element that retains its properties?

What is the charge of an electron?

Atoms can be broken down into smaller pieces.

Na is the chemical symbol for ______.

What does a chemical formula represent?

What is the atomic number of an element?

The atomic mass is the sum of protons and electrons.

A number placed to the lower right of a chemical symbol is called a ______.

In a chemical equation, what does the coefficient represent?

What happens during a chemical reaction?

What particles are present in the nucleus of an atom?

The number of protons and electrons is the same in a neutral atom.

How are electrons arranged around an atom?

What is the definition of a chemical reaction?

What is a neutron?