Bio 103 Chapter 2 & 3 test Questions and Answers with complete solution

The chemistry & physics of molecules that make up living organisms - Molecular Biology Compounds that do not have a carbon backbone - Inorganic Compounds A substance that cannot be broken down into simpler substances by ordinary chemical reactions - Element Each element is given a ________________. - Chemical Symbol These four elements make up 96% of the mass of most organisms - Oxygen, Carbon, Hydrogen, Nitrogen The smallest portion of an element that retains its chemical properties - Atom What are the subatomic parts of an atom? - Electron, Proton, Neutron Particle that carries a unit or negative electrical charge; not a part of the nucleus, move around the nucleus in spaces termed orbitals. Attracted to protons but repelled by other electrons. - Electron A unit of positive charge - Proton The uncharged particle - Neutron Proton & Neutrons found here - Atomic nucleus Each elements exact proton count - Atomic numberA chart in which elements are arranged by atomic number - Periodic Table Relates how massive one atom is to another; same as atomic nucleus; the mass is protons + neutrons - Atomic mass Found only in minute amounts of living organisms - Trace Elements In a basic form of an element, the number of protons equals the number of neutrons. In _______ the number of neutrons does not equal the number of protons. Each element can have several __________. - Isotopes -Hydrogen has three isotopes -This is why the atomic mass can have decimals -Isotopes are not stable and can break down Electrons move around the nucleus in spaces termed ________. _______ permits electrons to stay close to the nucleus and as far away from each other as possible. Each ______ contains one or two electrons. - Oribitals All of these orbitals with their electrons make up the _______ _______. - Electron Shell The outermost orbital is called _______ _____. - Valance Shell The electrons in the valance shell are called _______ ______. - Valance electrons 2 or more atoms combined - Molecule Consists of two or more atoms combined, atoms of different elements are combined - Chemical compound The written expression of a chemical compound - Chemical formula