Chapter 2 Test Study Guide

Question 1

Atoms

Answer 1

All matter is made of atoms everything that occupies space and has mass. Atoms are the smallest unit of matter: it cannot be broken, has a nucleus in the center with energy levels around the nucleus.

Question 2

3 Subatomic Particles

Answer 2

Particles that make up atoms

Question 3

Protons

Answer 3

In nucleus, positive charge

Question 4

Neutrons

Answer 4

In nucleus, neutral charge

Question 5

Electrons

Answer 5

Orbits nucleus/Energy levels, negative charge

Question 6

Elements

Answer 6

Pure substance that consists of one type of atom (many of the same atoms bonded together make an element)

Question 7

5 Most common in the human body:

Answer 7

Carbon
Nitrogen
Hydrogen
Oxygen
Phosphorus

Question 8

Identified by the number of protons (and how they are organized on the Periodic Table)

Answer 8

EX: Atomic number: 3. Element Symbol: Li. Atomic Mass: 6.94

Question 9

What does the Atomic # tell us?

Answer 9

How many protons are in an element

Question 10

How do we find the # of protons?

Answer 10

In the atomic number

Question 11

What is the maximum number of electrons in the first energy level surrounding the nucleus?

Answer 11

2

Question 12

What is the maximum number of electrons in the second energy level surrounding the nucleus?

Answer 12

8

Question 13

What is the maximum number of electrons in the third energy level surrounding the nucleus?

Answer 13

18

Question 14

What are chemical compounds?

Answer 14

A combo of 2 or more elements, when combined, compounds become their own unique substance. (the properties of compounds are different from the elements that form them).

Question 15

What is an ionic bond?

Answer 15

Ionic Bonds: Transfer electrons from one element to another.

Question 16

What is a covalent bond?

Answer 16

Covalent Bonds (valence electrons: the electrons in the outermost orbit): Share electrons between atoms.

Question 17

What do the bonds have in common?

Answer 17

Both are strong bonds.

Question 18

What is a water molecule made of?

Answer 18

Two hydrogen and one oxygen

Question 19

What charge does the O atom in water have?

Answer 19

A negative charge

Question 20

What is the charge of The H atoms in water

Answer 20

A positive charge

Question 21

Water is a polar molecule. What does that mean?

Answer 21

There is an unequal distribution of charges in a water molecule

Question 22

Where does the Hydrogen bond form between water molecules?

Answer 22

Attracting to oxgyen molecules

Question 23

What are the life-giving properties of water

Answer 23

Universal Solvent, Adhesion, Less Dense as a Solid, Cohesion, High Specific Heat

Question 24

Universal Solvent + its benefit

Answer 24

the polarity of water helps many substances dissolve in water. benefit: water can dissolve and transport + vitamins, nutrients, and minerals wherever it goes. solvent: substance doing the dissolving. solute: substance being dissolved. oil and water do NOT DISSOLVE well together.

Question 25

Adhesion + its benefit

Answer 25

the attraction of molecules of a different kind. benefit: allows water to move from the roots to the top of a plant

Question 26

Less Dense as a Solid + its benefit

Answer 26

water molecules are less tightly packed when frozen (solid) than when a liquid. benefit: lakes and ponds freeze from freezing by insulating them from freezing air temps

Question 27

Cohesion + its benefit

Answer 27

the attraction of molecules to other molecules of the same kind. benefit: allows water to move from the roots to the top of a plant

Question 28

High Specific Heat + its benefit

Answer 28

the amount of heat that must be absorbed or lost for water to change 1 degree C. Benefit: allows aquatic organisms to maintain homeostasis by regulating body temp, allows humans to live by regulating air temp

Question 29

What are heterogenous and homogeneous mixture?

Answer 29

Heterogeneous: Visibly different substances or phases. ex: water + ice, salad dressing, salad. Homogeneous: Same uniform appears throughout. ex: water, jello.

Question 30

What is a pH scale?

Answer 30

Water dissociates when mixed with an acid or base (water separates and breaks down). When acids dissolve in water, they release H+ ions.

Question 31

What does a pH scale measure?

Answer 31

Measures the concentration (neutral water) of hydrogen ions (H+)

Question 32

What are characteristics of acids?

Answer 32

- Have a pH < 7 - More acidic - Tastes sour - Have a high concentration of H+ ions

Question 33

What are characteristics of bases?

Answer 33

- Have a pH > 7 - The higher the pH, the more basic they are - Tastes more bitter - Have a high concentration of OH ions (low H+ ions)

Question 34

What are buffers?

Answer 34

Helps keep the pH of the body constant by preventing sudden changes in pH (maintain homeostasis!!). Also helps organisms maintain the pH of body fluids within the narrow range acceptable for life. Ex: Tums.