Chemical Basis of Life

Question 1

What is an element?

Answer 1

A substance that cannot be broken down into other substances by ordinary chemical means

Question 2

Which 4 elements make up 96% of the weight of the human body?

Answer 2

Hydrogen, Oxygen, Carbon and Nitrogen

Question 3

What is a compound?

Answer 3

A substance consisting of 2 or more different elements combined in a fixed ratio

Question 4

What is an atom?

Answer 4

The smallest unit of matter that still retains the properties of an element

Question 5

What are the 3 types of subatomic particles?

Answer 5

Proton, electron and neutron

Question 6

What are the different charges of each type of subatomic particle?

Answer 6

Proton - a single positive charge
Neutron - no charge
Electron - a single negative charge

Question 7

What is the core of an atom called?

Answer 7

Nucleus

Question 8

In regards to chemistry, what is the nucleus?

Answer 8

It is the core of an atom

Question 9

What do you call a substance that cannot be broken down into other substances by ordinary chemical means

Answer 9

An element

Question 10

What do you call a substance consisting of 2 or more different elements combined in a fixed ratio

Answer 10

A compound

Question 11

What is the atomic number of an element?

Answer 11

The number of protons in an atom of that element

Question 12

What is the mass number of an element?

Answer 12

The sum of the protons and neutrons in one atom of the element being considered

Question 13

What do you call the sum of the protons and neutrons in one atom of a specified element?

Answer 13

The mass number

Question 14

All atoms of an element have the same _____ number

Answer 14

Atomic

Question 15

If all atoms of an element have the same ____, then they all have the same number of _____ in their nucleus.

Answer 15

a) atomic number, protons

b) mass number, neutrons

Question 16

The different _____ of an element have the same numbers of protons and electrons, but they have a different numbers of neutrons.

Answer 16

isotopes

Question 17

What is a radioisotope/radioactive isotope?

Answer 17

“any of several species of the same chemical element with different masses whose nuclei are unstable and dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta, and gamma rays.”

Question 18

What is an ion?

Answer 18

An ion is an atom or molecule with an electrical charge resulting from a gain or loss of one or more electrons

Question 19

Define ionic bond

Answer 19

type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound. Such a bond forms when the valence (outermost) electrons of one atom are transferred permanently to another atom. The atom that loses the electrons becomes a positively charged ion (cation), while the one that gains them becomes a negatively charged ion (anion).

Question 20

Define covalent bond

Answer 20

the interatomic linkage that results from the sharing of an electron pair between two atoms. The binding arises from the electrostatic attraction of their nuclei for the same electrons. A covalent bond forms when the bonded atoms have a lower total energy than that of widely separated atoms.