Biology 111 - Chapter 1: Chemistry

a substance that cannot be broken down to other substances by chemical reactions

Element

a substance consisting of two or more elements in a fixed ratio

Compound

A compound has characteristics different from those of its elements. This can be referred to as an ______

Emergent property

those required by an organism in minute quantities

Trace Elements

What does iodine deficiency lead to?

Goitres (thyroid swelling)

What 4 elements make up 96% of living matter?

carbon, hydrogen, oxygen, nitrogen

What other elements make up the remaining 4%

phosphorus, potassium, sodium, sulfur, calcium, and magnesium

What percent of the 92 elements are essential to life

20-25%

the smallest unit of matter that still retains the properties of an element, has two regions.

Atom

What do he elements properties depend on?

the structure of its atoms

what are atoms composed of?

Subatomic particles

Negatively charged subatomic particle

Electron

Positively charged subatomic particle

Proton

Subatomic particle with no charge

neutron

number of protons in its nucleus

atomic number

the sum of protons plus neutrons in the nucleus.

mass number

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

Atomic mass

different forms of an element that have the same number of protons but a different number of neutrons.

Isotope

'decay spontaneously, giving off particles and energy

Radioactive isotopes

What is radioactive isotopes used for?

dating fossils, and diagnosing medical disorders

the capacity to cause change. determines interactions and chemical reactions.

Energy

the energy that matter has because of its location or structure

Potential energy

what is the electrons state of potential energy called?

electron shell, or energy level

the electrons of an atom differ in their amounts of ______

potential energy

what does the process of photosynthesis depend on?

excitations in electrons

what are valence electrons?

electrons in the outermost shell/ valence shell

• chemical behaviour of an atom is determined by ______

distribution of electrons in electron shells

what is the maximum number of electrons in the innermost shell?

2 electrons

what is the maximum number of electrons in the next two shells?

8 electrons

linkages between two or more atoms

bonds

consist of 2 or more atoms bound together by chemical bonds

molecules

• sharing of two pairs of valence electrons

• more stable and difficult to break

• rare to see

• two pair of electrons hold the nuclei together and closer

double covalent bonds

• sharing of one pair of valence electrons

• only one pair of electrons holding the nuclei together

• most common

single covalent bond

• one atom is more electronegative

• atoms do not share the electron equally

• if electronegativity is equal or greater than 0.5

polar covalent bond

• 2 non metals with same type of element (H-H)

• atoms share the electron equally

• if electronegativity difference is less than 0.5

non polar covalent bond

Sharing of electrons on valence shells

• can be polar or non polar 

• can be single or double bonded

covalent bond

linkages between two or more atoms

bonds

transfer of an electron from one atom to another

• attraction between an anion and cation

• opposites attract

• charged atom is an ion

• metal + non metal

Ionic Bond

negatively charged ion

anion

positively charged ion

cation

amount of attractiveness an atoms nucleus has for electrons

electronegativity

bonds between the molecules.

• individually weak but collectively strong

intermolecular bond

bonds within the molecule

• strong

intramolecular bond

forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom.

• always polar

• whenever hydrogen is attached to oxygen, or nitrogen

hydrogen bonds

attractions between molecules - or intermolecular interactions.

• hydrogen bonds are a special case of this

• are all hydrogen bonds, however, not all hydrogen bonds are all what they are

• individually very weak, collectively, such interactions can be strong.

• allows geckos to stick to a wall (their foot hairs rely on this)

• happen because of tiny, temporary changes in how electrons are distributed around atoms or molecules.

Van Der Waals Interactions