chem chapter 2: atoms, molecules, ions

Dalton’s Atomic Theory #1

all matter consists of atoms; tiny indivisible particles that cannot be created or destroyed

Dalton’s Atomic Theory #2

Atoms of one element cannot be converted into atoms of another element

Dalton’s Atomic Theory #3

Atoms of an element are identical in mass and other properties but are different from the atoms of any other element

Dalton’s Atomic Theory #4

Compounds result from the chemical combination of a specific ratio of atoms of different elements

The Law of Conservation of Mass

states that matter cannot be created or destroyed

The Law of Constant Composition

states that a specific compound is composed of the same elements in the same mass fractions

The Law of Multiple Proportions

states if elements and A and B react to form two compounds, the different masses of B that combine with a fixed mass of A can be expressed as a ration of small whole numbers

nucleons

protons and neutrons can be described as…

atomic number(z)

the number of protons in the nucleus of an atom that also determines the identity of the atom

neutral atom

an atom in which the total positive charge is equal to the total negative atom

groups

vertical columns on the periodic table that contain a “family” of elements that are most chemically similar to eachother

periods

horizontal rows on the periodic table that display a predictable repeating pattern of chemical properties

mass number(A)

the number of protons plus the number of neutrons, not on the periodic table

atomic symbol(X)

the element symbol from the period table

isotopes

atoms of the same element that have the same number of protons but a different number of neutrons, so they have the same atomic number but a different mass number

ion

an atom that has lost or gained one or more electrons

cation

positively charged ion

anion

negatively charged ion

atomic mass(amu)

weighted average of an elements masses of isotopes present in a natural sample, reported on the periodic table