Chem 131 Lecture 1: Intro to Atoms and Subatomic Particles

Vocabulary flashcards generated from Chem 131 lecture notes covering atomic theory, subatomic particles, atomic numbers, isotopes, periodic table organization, and ions.

Chemistry

The study of matter.

Matter

Anything that has mass and takes up space.

Dalton's Theory of the Atom (1803)

A theory establishing that: 1. Elements are made up of tiny indestructible particles called atoms; 2. Atoms of one element cannot change into atoms of another element (only changing the way they are bound); 4. Atoms combine in whole number ratios to form compounds.

Proton ($p^+$)

A subatomic particle defining the identity of the element, with a mass of $1.67262 \times 10^{-27}$ and a charge of $1+$.

Neutron ($n$)

A subatomic particle that can be stable or radioactive, with a mass of $1.67493 \times 10^{23}$ and a charge of $0$.

Electron ($e^-$)

A subatomic particle that determines the charge and reactivity of an atom, with a mass of $0.00091 \times 10^{-27}$ and a charge of $1-$.

Group Numbers

The vertical columns on the Periodic Table.

Period Numbers

The numbers that run horizontally across the Periodic Table.

Isotope

Two (or more) atoms that have the same number of protons ($p^+$) but a different number of neutrons (e.g., C-12 & C-14, Co-59 & radioactive Co-60).

Atomic Number ($Z$)

An integer value on the periodic table representing the number of protons an atom has.

Average Atomic Mass / Molar Mass

The non-integer number on the bottom of an element on the periodic table tells what?

Neutral Atom

An atom where the number of electrons is equal to the number of protons in its nucleus (designated by atomic number $Z$).

Ion

A charged particle formed when an atom loses or gains electrons ($e^-$) during chemical changes.

Cation

A positively charged ion formed by the loss of electrons ($e^-$).

Anion

A negatively charged ion formed by the gain of electrons ($e^-$).