CH.2 Atoms, Molecules, Ions

What is the Law of Constant Composition

compunds have definite composition which means the relative number of atoms of each element in the compund is the same Ex: Water is always 2:1

What is the Law of Conservation of Mass?

Mass can not be created nor destroyed

Cathode rays are composed of what fundamental particle?

The electron

What is radioactivity

the spontaneous emission of high energy radiation by an atom first observed by Henri Becquerel

What are the 3 types of radiation

alpha particles (positively charged)

Beta particles (negatively charged)

Y rays (uncharged)

Where are protons and neutrons found

inside the nucleus

where are electrons located

traveling around the nucleus

What is the atomic number

the number protons in the nucleus of an atom

What are isotopes

atoms of the same element with different masses Ex: C12, C14

Forumal for atomic weight

∑[Isotopes x fractional]

What metals are in group 1A

Alkali metals

What metals are included in group 2A

Alkaline

Group 6A consists of what metals

Calcogens

Group 7A consists of what metals

Halogens

Group 8A consists of what metals

Noble gases

What are the diatomic Molecules

Hydrogen

Nitrogen

Oxygen

Fluorine

Chlorine

Bromine

Iodine

Empircal formulas

giving the lowest whole-number ratio of atoms of each element

Molecular compounds

give the number of atoms of each element in a compound

What are ions?

when an atoms loses or gains electrons

Cations are

formed when at least one atom loses an electron e+

Anions are

formed when at least one electron is gained e^-

Which postulates of Daltons atomic theory of mater is not true

Atoms of a given element are identical

Atoms are indestructible

Positive charged particles of radiation emitted from the decay of radioactive substances are known as

alpha particles