Ch2

Question 0

compound

Answer 0

•A compound is a substance consisting of two or more elements in a fixed ratio

Question 1

element

Answer 1

•An element is a substance that cannot be broken down to other substances by chemical reactions

Question 2

Trace elements

Answer 2

•Trace elements are those required by an organism in minute quantities

Question 3

atom

Answer 3

•An atom is the smallest unit of matter that still retains the properties of an element

Question 4

Neutron

Answer 4

Non electrical charge

Question 5

Protons

Answer 5

Positive charge

Question 6

Electrons

Answer 6

Negative charge

Question 7

Atomic number

Answer 7

Is the number of protons in its nucleus

Question 8

Mass number

Answer 8

mass number is the sum of protons plus neutrons in the nucleus

Question 9

Atomic mass

Answer 9

•Atomic mass, the atom’s total mass, can be approximated by the mass number

Question 10

Isotopes

Answer 10

•Isotopes are two atoms of an element that differ in number of neutrons

Question 11

•Radioactive isotopes

Answer 11

•Radioactive isotopes decay spontaneously, giving off particles and energy

Question 12

Valence electrons

Answer 12

Valence electrons are those in the outermost shell, or valence shell

Question 13

Electron Orbitals

Answer 13

• An orbital is the three-dimensional space where an electron is found 90% of the time
• Each electron shell consists of a specific number of orbitals

Question 14

Concept 2.3: The formation and function of molecules depend on chemical bonding between atoms

Answer 14

• Atoms with incomplete valence shells can share or transfer valence electrons with certain other atoms
• These interactions usually result in atoms staying close together, held by attractions called chemical bonds