Chapter 4 Test Review Sheet

Democritus

Early Greek philosopher who proposed that matter is made of indivisible atoms.

John Dalton

Scientist who introduced a modern theory of the atom in the early 1800s.

J.J Thomson

Scientist who first detected the electron.

Ernest Rutherford

Scientist who first proposed the existence of a nucleus in the atom.

Electron

Subatomic particle discovered by J.J. Thomson, carrying a negative charge.

Plum Pudding Model

Thomson's vision of the atom, depicting a positive cloud with electrons dispersed throughout.

Rutherford's Experiment

Involved alpha particles directed at gold foil, some particles were deflected or rebounded.

Dalton's Atomic Theory

• elements are made of tiny, indestructable parts called atoms

• all atoms of each type of elements have the same mass

• atoms combine in simple, whole number ratios to form compounds

What did Rutherford's Atomic Model look like?

Depicted electrons orbiting a dense nucleus.

Protons

Positively charged particles found in the nucleus of an atom.

Neutrons

Neutral particles found in the nucleus of an atom.

Electron

Negatively charged particle that interacts with protons and other electrons.

Charge Neutral Atom

Contains an equal number of protons and electrons.

Atomic Number

Refers to the number of protons in an atom.

Element Definition

Defined by the number of protons it contains.

Nucleus has which particles?

Contains protons and neutrons.

Mass Number

Sum of protons and neutrons in an atom.

Dmitri Mendeleev

Scientist who developed the Periodic Table.

Periodic Table Categories

Metals (left), Metalloids (zig-zag line), Non-metals (right).

Metalloids

Elements with mixed properties, including Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Polonium, and Astatine.

Metals tend to form what kind of ion?

Tend to form positive ions by losing electrons.

Non-metals tend to form which kind of ion?

Tend to form negative ions by gaining electrons.

Metalloids

Used as semiconductors due to their mixed properties.

Characteristics of Metals

Good conductors, malleable, ductile, shiny, tend to lose electrons in chemical reactions.

Characteristics of Non-metals

Poor conductors, tend to gain electrons in chemical reactions.

Main Group Elements are found in which columns?

1, 2, 13- 18 of the Periodic Table.

Transition Metals, which columns?

3-12 of the Periodic Table.

Family Groups of columns 1, 2, 17, 18

Alkali metals (column 1), Alkaline earth metals (column 2), Halogens (column 17), Noble gases (column 18).

Pure Diatomic Molecules

Elements like Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, and Iodine that exist as pairs of atoms.

Ions

General term for elements that gain or lose electrons.

Cation

Positively charged ion.

Anion

Negatively charged ion.

Isotopes

Elements with a varying number of neutrons