Summary Science - Matter, Atoms, Elements, and Reactions

Fill-in-the-blank flashcards covering key concepts from the notes on substances, atoms, isotopes, and physical/chemical changes.

An is a substance made up of only one type of atom.

element

A is a substance made up of two or more types of atoms bonded together.

compound

The smallest particle of an element is the .

atom

A is a group of atoms bonded together.

molecule

A is a combination of substances that can be physically separated.

mixture

The number is the number of protons in each atom.

atomic

The mass number is the sum of and neutrons.

protons

Atoms of the same element with different mass numbers are .

isotopes

Different isotopes of an element are identified by their number.

mass

A stable isotope is one in which the nucleus is unlikely to .

break apart

An unstable isotope is one in which the nucleus is likely to .

break apart

A reaction shows color change and temperature change.

chemical

Deposition is a physical change from a gas to a .

solid

A change results in no new substances formed but can change shape.

physical

Sublimation is a physical change from a solid to a .

gas

Oxygen is written in chemical formula as .

O2

Nitrogen is written in chemical formula as .

N2

Mendeleev arranged the elements by increasing atomic .

mass

Today the periodic table is arranged by increasing atomic .

numbers

All isotopes have the same number of .

protons

The number of neutrons equals mass number minus .

atomic number

A proton has a positive .

charge

Cations are ions formed when an atom loses electrons and become a ion.

positive

Anions are ions formed when an atom gains electrons and become a charge.

negative

In a , particles are close together but can slide past one another.

liquid

The three fundamental states of matter are solid, liquid, and .

gas

Electrons orbit the .

nucleus

Negative ions are attracted to ions.

positive

An is a variation of an element with a different number of neutrons.

isotope

The mass number is the sum of protons and .

neutrons

The charge of a proton is .

positive

Ions result from the loss or gain of one or more .

electrons

Mg2+ is a ion.

cation

In chemical equations, the state of a solid is indicated by the symbol .

s

Isotopes have different numbers of .

neutrons

Electrons have a negative .

charge

In a neutral atom the numbers of protons and electrons are .

equal