Greek philosopher Democritus
Where did the concept of the atom come from?
What do atoms contain?
Protons, neutrons, and electrons
What are the subatomic particles that makeup an atom?
Strong forces bind protons and neutrons together at the center of the atom
A negatively charged particle with only 1/1840 the mass of a proton and are in constant motion in the space surrounding the nucleus
Positively charged nucleus and because of their motion
What are electrons attracted to and why do they remain outside the nucleus?
Equal number of electrons and protons
What makes atoms electrically neutral?
A pure substance that consists entirely of one type of atom
Over 100 elements are known, but only two dozen are commonly found
How many elements are known and how many are commonly found in living organisms?
One or two letter symbols
How are elements represented?
The number of protons in the nucleus of an element
Atoms of the same element that differ in the number of neutrons they contain
The total number of protons and neutrons in the nucleus of an atom
Isotopes whose nuclei are unstable and break down at a constant rate over time
Detect and treat cancer and to kill bacteria that cause food to spoil
What are some positive things about radiation from certain isotopes?
A substance formed by the chemical combination of two or more elements in definite proportions
Various types of chemical bonds
What holds the atoms in compounds together?
The electrons that are available to form bonds
Ionic and covalent
What are the main types of chemical bonds?
Formed when one or more electrons are transferred from one atom to another
Equal number of protons and electrons
Positively and negatively charged atoms
When an atom gains an electron, it has a _______ charge
When an atom loses an electron, it has a _______ charge
Electrons traveling about the nuclei of both atoms
The structure that results when atoms are joined together by covalent bonds
van der Waals forces
When molecules are close together, a slight attraction can develop between the oppositely charged regions of nearby molecules
Oxygen, nitrogen, fluorine
What are the most common partially negative atoms involved in hydrogen bonding?
The attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge
An attraction between molecules of the same substance
Why are some insects and spiders able to walk on pond's surface?
An attraction between molecules of different substances
One of the forces that draws water out of the roots of a plant and up into its stems and leaves
Water's heat capacity is high or low?
A material composed of two or more elements or compounds that are physically mixed together but not chemically combined
The substances that is dissolved
The substance in which the solute dissolves
When a material does not dissolve when placed in water, but separates into pieces so small that they do not settle out
A measurement system used to indicate the concentration of H+ ions in solution
Solutions with a pH below 7
Solutions with a pH higher 7
Solutions with a pH of 7
Any compound that forms H+ ions in solution