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

A _____ is a substance composed of two or more elements in a fix ratio

A ______ has characteristics different from those of its elements

_______ are those required by an organism in minute quantities.

The effect of ______ ________ in corn. In this controlled experiment, plants on the left are growing in soil that was fertilized with compounds containing nitrogen, while the soil on the right is deficient in nitrogen.

Goiter, an enlarged thyroid gland, is the result of a deficiency of the trace element _______. The goiter of this Malaysian woman can probably be reversed by iodine supplements.

An element’s properties depend on the structure of its ______

Each element consists of unique _____

•Atoms are composed of __________

•Neutrons and protons form the _________

Relevant subatomic particles include:

________ form a cloud around the nucleus

______ of the various elements differ in number of subatomic particles

•An element’s __________ is the number of protons in its nucleus

•An element’s _________ is the sum of protons plus neutrons in the nucleus

________ are two atoms of an element that differ in number of neutrons

•Electrons move around the nucleus only at a certain energy levels called _________

•Within each shell, electrons travel in different _______

•An ________ is the three-dimensional space where an electron is found 90% of the time.

•Each electron shell consists of a specific number of ______

____________ are those in the outermost shell, or valence shell. The chemical behavior of an atom is mostly determined by the __________

•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 _____ _____

•A ____ ____ is the sharing of a pair of valence electrons by two atoms.

•A _______consists of two or more atoms held together by covalent bonds

•A ____ ______, is the sharing of one pair of valence electrons

•A ____ ____, is the sharing of two pairs of valence electrons

the strongest kind of chemical bond

•In a _____ ___ the shared electrons count as part of each atom’s valence shell.

_______ can form between atoms of the same element or atoms of different elements

•In a ______ ______ ______, the atoms share the electron equally (methane)

•In a____ ____ _____, one atom is more electronegative, and the atoms do not share the electron equally (water)

Bonding electrons shared equally between two atoms. No charges on atoms.

Bonding electrons shared unequally between two atoms. Partial charges on atoms.

Complete transfer of one or more valence electrons. Full charges on resulting ions.

•A ______ is a positively charged ion

•An _____ is a negatively charged ion

•An _______ is an attraction between an anion and a cation

•Compounds formed by ____ _____ are called ionic compounds, or salts

•A _____ ______ forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom

__________ are the making and breaking of chemical bonds

•The starting molecules of a chemical reaction are called ______

•The final molecules of a chemical reaction are called _____

With four valence electrons, carbon can form four covalent bonds with a variety of atoms. This_______makes large, complex molecules possible

In molecules with multiple carbons, each carbon bonded to four other atoms has a _____ ______

When two carbon atoms are joined by a double bond, the molecule has a ____

CH4

C2H6

C2H4

_______are compounds with the same molecular formula but different structures and properties

_____ _____ have different covalent arrangements of their atoms

_____ ____ have the same covalent arrangements but differ in spatial arrangements

_________ are isomers that are mirror images of each other

In _____ the carbonyl group is at the end of the carbon chain and so has at least one hydrogen attached to it.

In _____ the carbonyl group is in the middle of a carbon chain and so it has two alkyl groups attached to it.

helps pull water up through the microscopic vessels of plants

is a measure of how hard it is to break the surface of a liquid

is the bonding of a high percentage of the molecules to neighboring molecules

_____ has an affinity for water

_____ does not have an affinity for water

a/an ____ is any substance that increases the hydrogen ion concentration of a solution

a/an _____ is any substance that reduces the hydrogen ion concentration of a solution

All living things are made up of four classes of large biological molecules:

A _______is a long molecule consisting of many similar building blocks. These small building-block molecules are called _____.

............ occurs when two mononers bond together through the loss of a water molecule

Polymers are disassembled to mononers by ......... a reaction that is essentially the reverse of the ....... reaction

........... include sugars and polymers of sugars

They serve as fuel and building materials

•A ______ is formed when a dehydration reaction joins two monosaccharides

__________, the polymers of sugars, have storage and structural roles

a linear chain of glucose molecules; it is poorly soluble in water and slowly digestible

a branched chain of glucose molecules; it is more soluble in water and more easily digestible