Science Chapter 5 8th Grade

Mendeleev

he set up the 1st periodic table according to the *increasing atomic mass*

Moseley

he set up the modern day periodic table according to *increasing atomic number*

1. Solids, liquids, or gases

2. Naturally occurring or those that do not occur naturally

3. Metals, nonmetals, metalloids

What are the 3 ways elements are classified?

Metals

the majority of the elements on the periodic table

Metals

located to the left of the zig-zag line

Metals

are good conductors of heat and electricity, mostly solids, malleable, have luster, and are ductile

Nonmetals

located to the right of the zig-zag line

Nonmetals

has properties opposite of metals

Nonmetals

poor conductors of heat and electricity, not solids, malleable, luster, or ductile

Metalloids

border the zig-zag line

Metalloids

have properties that fall between metals and nonmetals

Semi-conductors

having different properties that fall between metals and nonmetals

Groups (families)

the vertical columns on the periodic table (18 groups)

Families

What is another name for groups?

True

True or False: Elements that are in the same group or family have similar properties

Periods

the horizontal rows on the periodic table (7 periods)

Valence Electrons

the electrons that are located in the outermost energy level of the atom

Valence Electrons

Elements in a group have similar properties because they have the same number of ________ ___________

Ability

The number of valence electrons also determines the atom's _______ to form bonds with other atoms

Alkali Metals

the most reactive metals, so they are usually not found alone in nature (they are found as compounds). Group 1 on the periodic table

Alkali Metals

known as "soft metals", have low melting points and low densities

Soft Metals

have low melting points and low densities

Sodium (Na)

found in salt

Potassium (K)

found in bananas

Valence Electrons

Group # = # of ________ _____

Alkaline Earth Metals

reactive but not as reactive as the alkali metals. Group 2 on the periodic table

Calcium (Ca)

found in bones, teeth, and shells

Magnesium (Mg)

strong, light metal in airplanes, tennis racquets, and bicycles

Transition Metals

groups 3-12 on the periodic table. Conducts heat and electricity, malleable, and is ductile

Mercury

the only metals that is liquid at room temperature

Rare-Earth Metals

the last 2 rows at the bottom of the periodic table (periods 6 and 7)

Synthetic

created in the lab

Rare-Earth Metals

placed at the bottom of the periodic table for a more convenient size

Boron Group

group 13 on the periodic table

Aluminum (Al)

most abundant metal in the earth's crust (cans, gutters, and siding)

Boron (B)

used to make lab glassware that doesn't shatter when it undergoes a rapid change in temperature

The Carbon Group

group 14 on the periodic table

Carbon (C)

found in diamonds and graphite and in every living thing

Silicon (Si)

found in sand and glass and computer chips

Tin (Sn)

found in cans

Lead (Pb)

in dentists aprons to block x-rays

The Nitrogen Group

group 15 on the periodic table

Nitrogen (N)

78% of air. Also found in fertilizers, bombs, and DNA

Arsenic (As)

is poisonous

Phosphorous (P)

found in bones, fertilizers and DNA

The Oxygen Group

group 16 on the periodic table

Oxygen (O)

21% of the air

Sulfur (S)

yellow solid (smells like rotten eggs), used to make sulfuric acid (fertilizers and car batteries)

The Halogens

highly reactive nonmetals. Group 17 on the periodic table

"Salt formers"

What does the Halogens group mean?

Fluorine (F)

used in toothpaste and water supplies (kills bacteria)

Chlorine (Cl)

used in pools and water to kill bacteria, found in bleach, and salt (NaCl)

Iodine (I)

keeps your thyroid gland working properly (prevents goiter), antiseptics, found in some salts

The Noble Gases

have filled outer energy levels

group 18 on the periodic table

elements are nonreactive (inert)

colorless and odorless gasses

used in neon signs for light

Helium (He)

found in balloons and blimps

inert

another word for nonreactive

Shell Diagrams

shows the arrangement of the electrons on the energy levels in an atom

shell diagrams

shows what is inside the nucleus

Electrons

the number of energy levels an atom has depends on the total number of _______

1; 8

1st energy level: ___ electrons

The rest of the energy levels fill up to _ electrons

Octet Rule

up to 8 electrons

1) # of valence electrons = group #

2) # of energy levels = period # on the table

Shells diagrams tell us what 2 things?

Larger

As you go down in the periodic table, the size of the atom gets ________

Smaller

As you go across a period, the size of the atom gets _______

Bottom

The most reactive *metal* is at the (top or bottom) of the group?

Top

The most reactive *nonmetal* is at the (top or bottom) of the group