Chapter 2- Chemical Composition Of Body

Question 1

What are chemical elements?

Answer 1

Each type of atom–carbon, hydrogen, oxygen, etc. is called a chemical element

Question 2

What is an atom composed of?

Answer 2

Protons, neutrons, and electrons

Question 3

The atomic nucleus is composed of what?

Answer 3

Protons and neutrons are confined to the atomic nucleus

Question 4

What are orbitals?

Answer 4

The orbitals are where the electrons revolve around the nucleus. Each orbital can hold two electrons.

Question 5

What is an atomic number?

Answer 5

An atomic number is the specific number of protons that a chemical element contains

Question 6

What’s atomic weight?

Answer 6

Atomic weight is an atom’s mass relative to the mass of other atoms measured in daltons

Question 7

What are isotopes?

Answer 7

Isotopes are multiple forms of an atom, that does not have the same number of neutrons and protons.

Question 8

What is gram atomic mass?

Answer 8

Gram atomic mass is the amount of an element in grams, equal to the numerical value of its atomic weight

Question 9

What is an ion?

Answer 9

When an atom gains or loses one or more electrons and acquires a net electrical charge. Ions with a net positive charge are called cations and those with a net negative charge are called anions

Question 10

What are electrolytes?

Answer 10

Ionic forms of mineral elements that are able to conduct electricity when dissolved in water

Question 11

What are trace elements?

Answer 11

Thirteen essential elements present in small quantities but are essential for normal growth and function

Question 12

What’s a molecule?

Answer 12

A molecule is two or more atoms bonded together

Question 13

What’s a compound?

Answer 13

A molecule made up of two or more different elements

Question 14

What’s a covalent bond?

Answer 14

The strongest bond between two atoms which forms when one or more electrons transfer from the outer energy shell of one atom to that of another, or when two atoms with partially unfilled electron orbitals share electrons

Question 15

What is electronegativity?

Answer 15

It’s the measure of an atom’s ability to attract electrons in a covalent bond

Question 16

What is a polar covalent bond?

Answer 16

A covalent bond where the more electronegative atom acquires a slight negative charge, whereas the other atom, having partly lost an electron, becomes slightly positive

Question 17

What are polar molecules?

Answer 17

Polar molecules have polar covalent bonds and tend to be more soluble in water

Question 18

What are nonpolar covalent bonds?

Answer 18

A bond where the electrons are equally or nearly equally shared by the two atoms.

Question 19

What are nonpolar molecules?

Answer 19

Nonpolar molecules contain high proportions of nonpolar covalent bonds and tend to be less soluble in water

Question 20

What are hydrogen bonds?

Answer 20

Hydrogen bonds are formed when two polar molecules are in close contact, and an electrical attraction forms between them. Weakest of bonds but when large numbers are present, they play a major role in the shape of large molecules

Question 21

What are atoms?

Answer 21

The units of matter that form all chemical substances