States of Matter, Kinetic Molecular Theory, and Atomic Structure

Flashcards covering states of matter, kinetic molecular theory, atomic structure, and related concepts.

What are the three states of matter?

Solid, Liquid, and Gas

What are the properties of a mixture?

The components are not in a fixed ratio, they keep their own properties, and they can be separated easily by physical means.

What is a homogeneous mixture?

A mixture with a uniform composition where all components are in the same state.

What is a heterogeneous mixture?

A mixture with a non-uniform composition where particles can be distinguished.

How can components of a pure substance be separated?

Only by chemical means.

What does the particle model of matter state?

All matter is made up of tiny moving particles with spaces between them.

Define Brownian Motion.

The random motion of microscopic particles in a liquid or gas, caused by collisions with molecules of the liquid or gas.

Define Diffusion.

The movement of particles of a substance from a high to a low concentration.

What is Freezing Point?

The temperature at which a liquid completely changes into a solid when heat is removed.

What is Melting Point?

The temperature at which a solid completely changes into a liquid when heat is added.

What is Boiling Point?

The temperature of a liquid at which the vapor pressure is equal to the surrounding atmospheric pressure.

Describe the particle movement in a solid.

Particles only vibrate.

Describe particle movement in a liquid

Particles move involuntary, but in a restricted fashion.

Describe particle movement in a gas.

Particles move randomly and quickly.

What happens to chemical composition during a change of state?

The chemical composition remains constant.

What does the Law of Conservation of Mass state in relation to state changes?

The total mass of the particles before and after a state change remains constant.

What remains constant during a state change?

The particle speed (kinetic energy) and temperature remain constant.

What happens to potential energy during a state change when particles move further apart?

Potential energy increases.

What are the key concepts regarding the kinetic-molecular theory and gases?

Gases consist of tiny particles far apart, in constant rapid motion, with elastic collisions and negligible forces of attraction or repulsion. The average kinetic energy depends on temperature.

Who proposed the idea of atoms as 'uncuttable' particles?

Democritus.

What are the main points of Dalton's atomic theory?

All elements are made of indestructible solid spheres (atoms). Atoms of the same element are identical. An atom is the smallest particle that can take part in a chemical reaction. Compounds are formed by combining atoms in fixed ratios.

What did J.J. Thomson discover?

Small negative particles inside atoms called electrons.

What was Rutherford's key discovery?

The positive charge of an atom is concentrated in a small nucleus.

What did Niels Bohr propose about electrons?

Electrons travel around the nucleus in circular orbits with specific energy levels.

Who discovered the neutron?

James Chadwick.

What did Schrodinger propose about electron location?

It is not possible to find the exact position of an electron, only the most probable regions called orbitals.

What subatomic particles are found in the nucleus?

Protons and neutrons.

What is the atomic mass unit (amu) based on?

The mass of carbon-12 atom.

What determines the element of an atom?

The number of protons.

What are isotopes?

Atoms with the same number of protons but different numbers of neutrons.

What is Relative Atomic Mass?

Indicates how many times the average mass of an atom is heavier than 1/12 the mass of a carbon atom.

What determines electron arrangement within an atom?

Electrons are arranged in positions of lowest possible energy, with different energy levels accommodating different numbers of electrons.

How are Cations formed?

Cations are positive ions formed when electrons are lost.

How are Anions formed?

Anions are negative ions formed when electrons are gained.

What is Pauli's exclusion principle?

Maximum of two electrons per orbital provided that they spin in opposite directions.

What is Hund's rule?

No pairing in p orbitals before at least one electron in each of them.

In spectroscopic electron configuration (spd) notation, what does the notation represent?

It represents a concise way to indicate the electron arrangement in an atom.

What is noble gas notation in electron configuration?

It makes use of the first preceding noble gas, which has a completely filled outer energy level.

What happens to electrons in positive ions?

Positive ions have lost electrons.

What happens to electrons in negative ions?

Negative ions have gained electrons.