Midterm 4 Review (7th)

Molecules

100

What is a molecule?

Multiple atoms bonded together

200

What is the little number called in this formula: H₂O

A subscript

300

Why do atoms bond?

To become more stable 

To obtain a full valence shell

400

How many TOTAL oxygen atoms are in the following: 

2C₆H₁₂O₆

12

500

What is the chemical formula for table sugar?

C₁₂H₂₂O₁₁

Bonds

100

BONUS 500 points!

What is a covalent bond?

A bond formed because atoms are sharing electrons (or fighting over them)

200

What is an ionic bond?

One atom loses electrons and another atom gains electrons. The opposite charges cause the atoms to be attracted to each other.

300

An ionic bond is formed between what kind of elements?

A metal and a nonmetal

400

What kind of bonds does this molecule have?

MgCl₂

Ionic! 

500

Why do elements in Group 5 usually take on a -3 charge?

They have 5 valence electrons, which means they want 3 more. As soon as they get 3 more electrons, they also get 3 more negative charges! 

Lewis Dot Diagrams

100

What is a chemical symbol? What does it have to do with Lewis Dot Diagrams?

The letter(s) on the Periodic Table that represent a specific element. In Lewis Dot Diagrams, we start by writing this symbol.

200

Draw the Lewis Dot Diagram for Carbon.

Answers vary.

300

Name 4 elements on the Periodic Table that have 7 valence electrons

F, Cl, Br, I

400

Draw the Lewis Dot Diagram for Nitrogen

Answers vary

500

Name 2 differences between Lewis Dot Diagrams and Bohr diagrams.

Protons and Neutrons are not shown. 

Inner electrons are not shown (only the valence electrons)

No orbitals/shells are actually drawn

Water

100

Give an example of cohesion.

Water-striders

200

BONUS 500 points!

What does adhesion mean?

A property of water that describes when it sticks to (or "adds itself") to other substances.

300

What are hydrogen bonds?

Attractions between water molecules, with the negative side of one molecule attracted to the positive side of another molecule.

400

Give an example of a hydrophobic substance.

Oil, butter, etc.

500

What does the word "polar" mean?

Two opposite ends.

Random

100

BONUS 500 points! 

Is table sugar an ionic or a covalent molecule?

Covalent

200

What does "hydrophobic" actually mean?

water-fearing

300

If you were to zoom in on an ionic molecule, what would the structure look like?

Regular crystalline structures.

400

What is the chemical formula for table salt?

NaCl

500

Which has a lower melting point: sugar or salt? And why?

Sugar

The attractions between covalent molecules is much weaker than between ionic molecules!