Chemistry Basics: Understanding Matter

Questions and Answers

Anything that has mass and occupies space.

The study of matter and its interactions.

1st shell (correct)

2nd shell

3rd shell

None of the above

Oxygen Signup and view all the answers

A substance that cannot be broken down to a simpler substance by chemical means. Signup and view all the answers

Atoms with the same atomic numbers but different mass numbers. Signup and view all the answers

Cooking food Signup and view all the answers

Atoms of two or more elements are physically intermixed Signup and view all the answers

A substance that dissolves. Signup and view all the answers

The amount of solute present in a solution. Signup and view all the answers

11 Signup and view all the answers

A charged particle. Signup and view all the answers

Valence electrons. Signup and view all the answers

Study Notes

An atom is the smallest unit of matter preserving original properties.
Atomic structure includes:
- 1st shell: holds 2 electrons
- 2nd shell: holds up to 8 electrons
- 3rd shell: can hold up to 18 electrons, usually stable at 8 electrons
An element is a substance that cannot be chemically broken down into simpler substances.
Elements are defined by their atomic number, which indicates the number of protons.
The periodic table organizes elements by chemical symbols, typically derived from their names (e.g., H for Hydrogen).

Isotopes have identical atomic numbers but different mass numbers.
Some isotopes are highly energetic and unstable, emitting radiation, utilized in nuclear medicine.
Applications of isotopes include:
- Cancer radiation therapy
- Radiotracers
- Treatment of thyroid disorders

A mixture consists of atoms from two or more elements physically intermixed.
Components of a solution:
- Solute: the substance that dissolves
- Solvent: the medium in which the solute dissolves (water is the primary solvent in the human body)
Concentration indicates the amount of solute in a solution (e.g., 10 grams of salt in 90 milliliters of water = 10% salt solution).
Solutions are mixtures formed without chemical changes, allowing for physical separation.

Valence electrons determine how atoms bond with others.
Example of ionic bonding: Sodium (Na) transfers its outer electron to Chlorine (Cl), resulting in charged particles known as ions.
Sodium has 11 protons and upon losing one electron, becomes a positively charged ion with a +1 charge.