Chapter 4: Atoms and Elements

Elements

These are pure substances from which all other things are built

Periodic Table

The arrangement of 118 elements

Period

Each horizontal row in the periodic table

Group

Each vertical column on the periodic table

Representative Elements

These have group numbers 1A to 8A

Transition Elements

These are block elements in the center of a periodic table that have group numbers followed by the letter ‘B

Group 1A

These are alkali metals except for Hydrogen

Group 2A

These are alkaline earth metals; these are shiny metals but not as reactive

Group 7A

These are halogens; highly reactive and form compounds with most of the elements

Group 8A

These are noble gases; they are quite unreactive and are seldom found in combination with other elements

lanthanides and actinides

The two rows of 14 elements called the ______, which are part of Periods 6 and 7, are placed at the bottom of the periodic table to allow them to fit on a page.

Metals

These are shiny solids, such as copper, gold, and silver

Nonmetals

They are often poor conductors of heat and electricity

Metalloids

These are elements that exhibit some properties that are typical of metals and other properties that are characteristic of nonmetals

Atom

The smallest unit particle of an element that retains the characteristics of that element

Subatomic Particles

These are even smaller bits of matter

Cathode Rays

These are streams of small particles produced when electricity is applied to a glass tube

Protons

These are the atoms positively charged particles

Electrons

These are the atoms negatively charged particles

Neutrons

These are the atoms neutral particles

Nucleus

The center of the atom

Atomic Mass Unit

A very small unit of mass

Dalton

The atomic mass unit

Atomic Number

This is equal to the number of protons in every atom of that element

Mass Numer

The total number of protons and neutrons in its nucleus

Number of neutrons in a nucleus = mass number

number of protons

Isotopes

These are atoms of the same element that have the same atomic number but different numbers of neutrons

weighted average

Because each isotope has a different mass, chemists have calculated an atomic mass for an “average atom,” which is a ______ of the masses of all the naturally occurring isotopes of that element.

Atomic Symbol

It indicates the mass number in the upper left corner and the atomic number in the lower left corner

Electromagnetic spectrum

It shows the arrangement of different types of electromagnetic radiation in order of increasing energy

atomic spectrum

When light from a heated element passes through a prism, it separates into distinct lines of color separated by dark areas called an _____.

principal quantum numbers

In an atom, each electron has a specific energy known as its energy level, which is assigned values called _____.

electron arrangement

The ______ of an atom gives the number of electrons in each energy level.

Period Properties

These consists of the valence electrons in atoms, the trends in atomic size, ionization energy, and metallic character

Valence Electrons

These are the electrons in the outermost energy level

Electron-Dot Symbol

Also known as a Lewis Structure, represents the valence electrons as dots that are placed on the sides, top, or bottom of the symbol for the element

Ionization Energy

A quantity of energy that is required to remove one of the outermost electrons

Cation

A positive particle

Anion

A negative particle.

Metallic Character

An element that loses valence electrons easily

According to Dalton’s Atomic Theory,

atoms

According to Dalton’s Atomic Theory, All matter is made up of tiny particles called ______.

similar to one another and different from atoms of other elements

According to Dalton’s Atomic Theory, All atoms of a given element are ______________.

compounds

According to Dalton’s Atomic Theory, Atoms of two or more different elements combine to form _______.

chemical reaction

According to Dalton’s Atomic Theory, Atoms are never created or destroyed during a ________.