2 Atoms, Elements, and the Periodic Table Free Online FlashCards

What determines an atom’s element?

An element’s identity is determined by its number of protons.

What does an element’s atomic number tell you?

The atomic number is the number of protons in an atom.

What is an atom’s mass number?

The mass number is the total number of protons and neutrons in a particular atom.

How do you calculate an atom’s number of neutrons?

Find neutrons by subtracting the atomic number from the mass number: $N=A-Z$.

How are electrons and protons related in a neutral atom?

In a neutral atom, the number of electrons equals the number of protons.

What makes two atoms isotopes of the same element?

Isotopes are atoms of the same element with different numbers of neutrons.

What does an element’s listed average atomic mass represent?

An element’s listed atomic mass is a weighted average based on the masses and natural abundances of its isotopes.

How does an atom become an ion, and how is its charge found?

An ion forms when an atom gains or loses electrons; its proton number does not change. Its charge is $p-e$, where $p$ is protons and $e$ is electrons.

What is a cation?

A cation is a positively charged ion formed when an atom loses electrons.

What is an anion?

An anion is a negatively charged ion formed when an atom gains electrons.

How are elements ordered in the periodic table?

The periodic table arranges elements in order of increasing atomic number.

What are periods, and how does atomic number change across one?

Periods are the seven rows of the periodic table. Atomic number increases from left to right across a row.