Chapter 2 - Essential Chem For Bio

Question 1

What is a trace element?

Answer 1

Very small amounts of elements but critical to humans and can’t live without them.

Question 2

What is matter ?

Answer 2

Anything that has mass and occupies space.

Question 3

What is an isotope?

Answer 3

Different forms of the same element.

Question 4

True or false. When identifying an element On the table of elements, the atomic number stays the same and the mass number can change.

Answer 4

True.

Question 5

2 or more atoms held together by a chemical bond.

Answer 5

What are molecules.

Question 6

What is a chemical bond ?

Answer 6

Attractions between atoms that involve transferring or sharing electrons.

Question 7

What does a reaction do?

Answer 7

Enables atoms to gain or lose electrons to fill the valence shell.

Question 8

True or false. The valence she’ll is the outermost orbit of elections.

Answer 8

True.

Question 9

What bonds and molecules make water ?

Answer 9

2 covalent bonds , 2 hydrogen and 1 oxygen.

Question 10

Name 3 properties of water.

Answer 10

• cohesion
• surface tension
• moderates heat energy
• low density
• good solvent

Question 11

A tool used to measure the H+ ion concentration.

Answer 11

What is the pH scale.

Question 12

How many important elements do humans need? Name the major 4.

Answer 12

25.  
•oxygen 
•carbon 
•hydrogen 
•nitrogen