Science 8th Grade - Topic 1 Lessons 3 & 4

What happened during the Hindenburg Explosion?

While the Hindenburg attempted to land in Lakehurst, New Jersey in 1937, a spark came into contact with hydrogen used to fill the airship, causing an instantaneous explosion that killed 36 people.

How could the Hindenburg Explosion be prevented? Why?

They could have used a less reactive element for fuel because then if it were to come in contact with a spark, it would not explode.

What are valence electrons?

Electrons in the outermost energy level.

Do valence electrons have higher or lower energy compared to electrons closer to the nucleus?

Higher.

Where are valence electrons located?

At the outermost shell of an atom.

Why are valence electrons important?

They keep an atom stable.

How do you determine how many valence electrons an element has?

The ones digit of the group number.

What is a Bohr diagram?

A Bohr diagram is a diagram that shows the number of electrons in each shell surrounding the nucleus of an atom.

What is an electron dot diagram?

Another way to represent valence electrons.

How are Bohr and electron dot diagrams similar?

They both show the amount of valence electrons an atom has.

What does APE stand for?

Atomic number = protons = electrons.

What does MAN stand for?

Mass number - atomic number = neutrons.

How many electrons can fit in the first energy level?

2

How many electrons can fit in the second energy level?

8

How many electrons can fit in the third energy level?

18

Luster

Refers to the way a metal's surface reflects light.

Ductile

Refers to the way most metals can be stretched into wires.

Malleable

Refers to the way most metals can be hammered or rolled into thin sheets.

Brittle

The tendency of material to fracture or fail with a small amount of force.

Conductivity

The measure of the ease at which an electric charge or heat can pass through a material.

Insulator

A material that keeps energy such as electricity, heat, or cold from easily transferring through.

Are metals malleable?

Yes

Are metals ductile?

Yes

Are metals good thermal conductors?

Yes

Are metals good electrical conductors?

Yes

Do metals have luster?

Yes

What can metals react with?

Nonmetals.

What phase are metals at during room temperature?

Most are solid.

Where are metals found on the periodic table?

The left and middle.

How many valence electrons do metals usually have?

1 to 6.

Are nonmetals malleable?

No

Are nonmetals ductile?

No

Are nonmetals good thermal conductors?

No

Are nonmetals good electrical conductors?

No

Do nonmetals have luster?

No

What can nonmetals react with?

Metals and nonmetals.

What phase are nonmetals at during room temperature?

Most are gasses.

Where are nonmetals found on the periodic table?

The right.

How many valence electrons do nonmetals usually have?

1 or 3-8.

Are metalloids good thermal conductors?

Better than nonmetals, but not as well as metals.

Are metalloids good electrical conductors?

Better than nonmetals, but not as well as metals.

Do metalloids have luster?

Thye can be.

What phase are metalloids at during room temperature?

Solid.

Where are metalloids found on the periodic table?

In between the metals and nonmetals. Boron the moron is at the top of the stupid stairs.

How many valence electrons do metalloids usually have?

3-7

What are ions?

An atom or group of atoms that has become electrically charged.

How do atoms become ions?

By losing or gaining electrons.

How do you know if an element will become a positive or negative ion?

If an atom gains a valence, it becomes a negative ion. If an atom loses a valence electron, it becomes a positive charge.

What is a polyatomic ion? Give an example.

An ion that is made of more than one atom like NH₄+.

What is ionic bonding?

The transfer of electrons.

Are ionic bonds good or bad conductors of thermal and electricity?

Good

Do ionic bonds have high or low melting points?

High

Are ionic bonds always soluble or sometimes soluble in water?

Always

Do ionic bonds form crystals?

Yes

What is covalent bonding?

The sharing of electrons.

Which elements form covalent bonds?

Metals and nonmetals.

Single Bonds

Atoms that share only one pair of electrons.

Double Bonds

Atoms that share two pairs of electrons.

Triple Bonds

Atoms that share three pairs of electrons.

What is a polar covalent bond?

A covalent bond in which electrons are not shared equally.

What is a nonpolar covalent bond?

A type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity.

How can a molecule with polar covalent bonds be a nonpolar molecule? Provide an example.

The atoms pull with equal strength in opposite directions like carbon dioxide.

Are covalent bonds good or bad conductors of thermal and electricity?

Bad

Do covalent bonds have high or low melting points?

Low

Are covalent bonds always soluble or sometimes soluble in water?

Sometimes

Do covalent bonds form crystals?

Yes

What does "like dissolved like" mean?

Polar dissolves polar and nonpolar dissolves nonpolar.