Chemistry Exam Study Guide

What is the definition of an isotope?

The same element with different masses because it has a different number of neutrons.

What is the relationship between atomic mass and mass number?

Atomic mass is the average of all isotopes, while the mass number is the total number of protons and neutrons in a single atom.

What are valence electrons?

Electrons on the outermost energy level that determine the reactivity of the atom.

How many valence electrons make an atom most stable?

8 valence electrons make an atom most stable, according to the octet rule.

What is a cation?

A positively charged particle.

What is an anion?

A negatively charged particle.

What are the six families on the periodic table?

Alkali metals, alkaline earth metals, transition metals, halogens, noble gases, and inner transition metals.

How can you identify a reaction type of combustion?

It always has O2 as a reactant and produces CO2 and H2O.

What does the law of conservation of mass state?

Matter is neither created nor destroyed, only changes form; seen when balancing an equation.

Why do noble gases not react with other atoms?

Noble gases are stable with 8 valence electrons and do not need to gain or lose electrons.

What defines a group/family on the periodic table?

A column (up and down) with similar properties due to having the same number of valence electrons.

What happens during an acid-base neutralization?

An acid and a base react together and produce water and a salt.

How many protons, neutrons, and electrons are in 172Yb?

Protons: 70, Neutrons: 102, Electrons: 70.

What is the most stable configuration of electrons for an atom?

Having 8 valence electrons, also known as the octet rule.

What is the symbol for an element?

The 1 or 2 letter abbreviation for the element.

What is the atomic number?

The number of protons in an atom, which is unique to each element.

What is the mass number?

The total number of protons and neutrons in an individual atom.

What happens when you add a proton to an atom?

The element changes and becomes positively charged.

What is the average mass of all isotopes of an element called?

Atomic mass.

What is a reaction that breaks down one reactant into multiple products called?

Decomposition.

What example of an endothermic reaction can you give?

Formation of ozone.

What happens when you remove an electron from an atom?

The element becomes positively charged.

In the context of the periodic table, what does 'period' refer to?

Rows (side to side) with similar sizes of atoms.

What is electric charge?

The physical property of matter that causes it to experience a force when placed in an electromagnetic field.

How do metals, nonmetals, and metalloids differ?

They differ in their physical and chemical properties; metals are generally conductive and malleable, nonmetals are insulative and brittle, and metalloids have properties of both.