Chapter 2.1 - Units of Matter Flashcards

Questions and Answers

What is an atom?

Basic unit of matter, made up of 3 subatomic particles.

What does the nucleus contain?

Protons and neutrons.

What do electrons do?

Move around the nucleus.

What is the atomic number?

The specific number assigned to each element that indicates the number of protons the atom has. Signup and view all the answers

What is a chemical element?

A pure substance that consists entirely of one type of atom. Signup and view all the answers

What is an element?

A substance that cannot be broken down into other substances. Signup and view all the answers

What are isotopes?

Atoms of the same element that differ in the number of neutrons. Signup and view all the answers

What is a compound?

A substance formed by the chemical combination of 2 or more elements in definite proportions. Signup and view all the answers

What are chemical bonds?

What the atoms in compounds are held together by. Signup and view all the answers

What are valence electrons?

Electrons that are available to form bonds. Signup and view all the answers

What happens in covalent bonds?

Electrons are shared. Signup and view all the answers

What happens in ionic bonds?

Electrons are transferred. Signup and view all the answers

What is a molecule?

Smallest unit of a compound. Signup and view all the answers

Study Notes

Units of Matter

An atom is the fundamental unit of matter, composed of three subatomic particles: protons, neutrons, and electrons.
The nucleus is the core of an atom, housing protons (positively charged) and neutrons (neutral).
Electrons are negatively charged particles that orbit the nucleus in defined energy levels.
The atomic number uniquely identifies each element, representing the total number of protons in its atoms.
A chemical element is defined as a pure substance made entirely of one type of atom, such as oxygen or gold.
An element cannot be broken down into simpler substances by chemical means.
Isotopes refer to variations of the same element that have the same number of protons but different numbers of neutrons, leading to different mass numbers.
A compound forms when two or more elements chemically combine in fixed ratios, resulting in distinct properties from the individual elements.
Chemical bonds are the forces that hold atoms together within compounds, essential for forming stable structures.
Valence electrons are the outermost electrons of an atom, crucial for bonding as they can be shared or transferred to form chemical bonds.
Covalent bonds occur when electrons are shared between atoms, allowing them to fill their outermost electron shells.
Ionic bonds form when electrons are transferred from one atom to another, resulting in the creation of charged ions that attract each other.
A molecule is the smallest functional unit of a compound, containing two or more atoms bonded together either through covalent or ionic bonds.

Description

Test your knowledge of key terms in Chapter 2.1 focusing on the units of matter. This quiz covers definitions related to atoms, nuclei, electrons, and chemical elements. Perfect for reinforcing your understanding of basic chemistry concepts.