Unit 1- Atomic Structure and Properties

What are the classifications of matter?

Pure substances (elements and compounds), homogeneous mixtures, and heterogeneous mixtures.

What makes a mixture homogeneous?

In homogeneous mixtures, different components are not visibly separate.

What is the structure of an atom?

An atom consists of a nucleus containing protons and neutrons, with electrons in orbitals around the nucleus.

What is the atomic number and how is it determined?

The atomic number is the number of protons in an atom and is identified from the periodic table.

How does one calculate atomic mass?

Atomic mass is the average of all isotope masses found in nature, which can be calculated from the percent abundance of each isotope.

Define isotopes.

Isotopes are variations of the same element that have different numbers of neutrons.

What is a cation?

A cation is an atom that has lost electrons and has a positive charge.

What does Coulomb’s Law describe?

Coulomb's Law describes the force between two charges, stating that the force increases with charge and decreases with distance.

What is Avogadro's Number?

Avogadro's Number is 6.022 x 10^23, representing the number of particles in one mole.

What are diatomic molecules?

Diatomic molecules are elements that naturally pair up, such as I2, Br2, Cl2, F2, O2, N2, and H2.

Explain the Aufbau Principle.

The Aufbau Principle states that lower energy levels must be filled before higher energy levels are occupied.

What is the Pauli Exclusion Principle?

The Pauli Exclusion Principle states that each orbital can hold 2 electrons, which must have opposite spins.

How does atomic radius change across a period and down a group?

Atomic radius decreases across a period due to increased effective nuclear charge and increases down a group due to added electron shells.

What is electronegativity?

Electronegativity is the ability of an atom to attract shared electrons in a bond.

What is ionization energy?

Ionization energy is the energy required to remove an electron from an atom.

Describe electron affinity.

Electron affinity is the energy released when

What is a compound?

A compound is a substance formed when two or more different elements are chemically bonded together.

What is a mixture?

A mixture is a combination of two or more substances where each substance retains its own properties.

What is the difference between an element and a compound?

An element is a pure substance that cannot be broken down into simpler substances, while a compound is made of two or more elements chemically combined.

Define a heterogeneous mixture.

A heterogeneous mixture has visibly different substances or phases and the components can often be separated mechanically.

What is a solution?

A solution is a homogeneous mixture where one substance (solute) is dissolved in another (solvent).

Explain the law of conservation of mass.

The law of conservation of mass states that mass cannot be created or destroyed in a chemical reaction; it is conserved.

What are the states of matter?

The states of matter are solid, liquid, gas, and plasma, characterized by differences in energy, particle arrangement, and movement.

What is an electron?

An electron is a negatively charged subatomic particle found in the outer regions of an atom, in orbitals around the nucleus.

Describe neutrons.

Neutrons are neutral subatomic particles found in the nucleus of an atom, contributing to its mass but not to its charge.

What role do protons play in an atom?

Protons are positively charged particles found in the nucleus of an atom, and their number determines the element's identity.

What is a chemical bond?

A chemical bond is the force that holds atoms together in a compound, which can be ionic or covalent in nature.

Define an ionic bond.

An ionic bond is a type of chemical bond formed through the electrostatic attraction between positive and negative ions.

What is a covalent bond?

A covalent bond is a type of chemical bond where two atoms share one or more pairs of electrons.

What are valence electrons?

Valence electrons are the outermost electrons of an atom and are involved in forming bonds with other atoms.