atom
building blocks of matter
element
pure substances that cannot be broken down chemically into simpler kinds of matter
matter
something that occupies space (solid, liquid, gas)
isotope
form of a particular chemical element which differ in neutron number
compound
pure substance made up of atoms of two or more elements
protons (positive) neutrons (neutral)
what particles are found in the nucleus of an atom? What are their charges?
electrons (negative)
what particles are found in the energy levels surrounding the nucleus? What are their charges?
2;8
what are the maximum amount of electrons in the 1st energy level?
The 2nd energy level?
nucleus
where is most of the mass of an atom found?
protons or electrons
on the Periodic Table of Elements- what is the atomic # equal to?
protons + neutrons
on the Periodic Table of Elements- what is the atomic mass equal to?
negative charge
when ions are formed, an atom gains an electron, what type of charge does it have?
positive charge
when ions are formed, an atom loses an electron, what type of charge does it have?
atoms become more stable when they bond together
why do atoms form chemical bonds?
positive and negative electrical charges attract each other
what is an ionic bond?
sodium chloride (NaCl)
what is an exampled of an ionic bond?
the sharing of electron pairs between atoms
what's a covalent bond?
H2O
what's an example of a covalent bond?
a process that involves rearranging the molecular or ionic structure of a substance
what's a chemical reaction
A physical change doesn't change what the substance actually is, but a chemical change is when a new substance is formed and energy is either given off or absorbed
what is the difference between a physical change and a chemical change?
crushing cans; chopping wood
examples pf physical; chemical change
reactants
In a chemical reaction, what are the substances that enter the reaction called?
products
In a chemical reaction, what are the substances that are produced called?
the amount of energy needed to start a chemical reaction
what is activation energy?
exothermic reactions are the net release of free energy and endothermic reactions are reactions that involve a net absorption of free energy.
what is the difference between and exothermic and an endothermic reaction?
biological catalysts; mostly protein, thousands of different kinds, and each are specific for a different chemical reaction.
what is an enzyme and why are they important to living organisms?
temperature, pH, enzyme concentration, substrate concentration, and the presence of any inhibitors or activators.
what factors can affect the functions of enzymes?