basic unit of matter
center of an atom and is made up of protons and neutrons
Is a proton positive, negative, or neutral?
Is a neutron positive, negative, or neutral?
Is an electron positive, negative, or neutral?
Why are atoms neutral despite having charged particles?
atoms have equal numbers of electrons and protons and subatomic particles have opposite charges
pure substance that consists entirely of one type of atom
an element's atomic number represents...
the number of protons in the atom
atoms of the same element that differ in the number of neutrons they contain
How are isotopes identified?
By their mass numbers
Why do all isotopes of an element have the same chemical properties?
They have the same number of electrons
substance formed by the chemical combination of two or more elements in definite proportions
holds atoms in compounds together
the bond that is formed when electrons are shared between atoms
the bond that is formed when one or more electrons are transferred from one atom to another
positively and negatively charged atoms
Does an atom that loses electrons have a negative charge?
structure that results when atoms are joined together by covalent bonds
Can atoms share six electrons and form a triple bond?
In a water molecule, how many covalent bonds do each hydrogen atom form?
True or false: When atoms show two electrons, it is called a double bond
the slight attractions that develop between oppositely charged regions of nearby molecules
Van der Waal's forces
Is a water molecule neutral?
Why is a water molecule polar? (Think of H2O)
there is an uneven distribution of electrons between the oxygen and hydrogen atoms
Is a hydrogen bond stronger than an ionic bond?
True or false: The attraction between the hydrogen atom on one water molecule and the oxygen atom on another water molecule is an example of a hydrogen bond.
strongest bonds that form between molecules
Is a hydrogen bond stronger than a covalent bond?
attraction between molecules of the same substance
attraction between molecules of different substances
Why is water extremely cohesive?
rise of water in a narrow tube against the force of gravity
How does capillary action affect plants?
it draws water out of the roots of a plant and up into its stems and leaves
material composed of two or more elements or compounds that are physically mixed together but not chemically combined
mixture of two or more substances in which the molecules of the substances are evenly mixed
What is the greatest solvent in the world?
mixture of water and non-dissolved materials
substance that is dissolved
substance in which the solute dissolves
two water molecules can react to form...
Why is water neutral despite the production of hydrogen ions and hydroxide ions?
the number of positive hydrogen ions produced is equal to the negative hydroxide ions produced
indicates the concentration of hydrogen ions in solution
True or False: Acidic solutions have pH values below 7
On a pH scale, what is neutral?
Do acidic solutions contain higher concentrations of H+ ions than pure water?
any compound that forms H+ ions in solution
compound that produces OH- ions in solution
weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH
How many valence electrons does each carbon atom have?
What gives carbon the ability to form chains that are almost unlimited in length?
a carbon atom can bond with other carbon atoms
many of the molecules in living cells are so large that they are known as...
process by which macromolecules are formed
When monomers join together, what do they form?
What are the four groups of organic compounds found in living things?
What atoms make up carbohydrates?
carbon, hydrogen, and oxygen
True or false: Living things use carbohydrates as their main source of energy
simple sugar molecules
What are two examples of a monosaccharide?
galactose and fructose
large molecules formed from monosaccharides
How do plants and animals store excess sugar?
in a polysaccharide called glycogen
What kinds of atoms are lipids mostly made up of?
carbon and hydrogen
Each carbon atom in a lipid's fatty acid chains is joined to another carbon atom by a single bond
At least one carbon-carbon double bond in a fatty acid
A lipid's fatty acids contain more than one double bond
Nucleic acids contain what kinds of atoms?
hydrogen, oxygen, nitrogen, carbon, and phosphorus
What kinds of acids do proteins contain?
What are two examples of a disaccharide?
lactose and maltose
What is one function of a lipid?
they can be used to store energy
What is one function of a nucleic acid?
they store and transmit hereditary, or genetic, information (think deoxyriboNUCLEIC ACID- DNA)
What is one function of a protein?
they can form bones and muscles