MTTC integrated Sciences 094 physical sciences Exam Questions With Correct Answers

Plasma - Answer ionized gas that has some electrons that are described as free because they are not bound to an atom or molecule specific gravity - Answer measurement of the density of substances in a liquid compared to water atomic theory - Answer a theory that states that all matter is composed of tiny particles called atoms. John Dalton - Answer developed modern atomic theory negative ion - Answer anion, gains electrons positive ion - Answer cation; loses electrons ionic bond - Answer Formed when one or more electrons are transferred from one atom to another Ionization - Answer neutral molecules gain or lose electrons valence electrons - Answer Electrons on the outermost energy level of an atom covalent bond - Answer A chemical bond that involves sharing a pair of electrons between atoms in a molecule hydrogen bond - Answer weak attraction between a hydrogen atom and another atom Van der Waals interactions - Answer Weak attractions between molecules or parts of molecules that result from transient local partial charges. 2 most abundant elements in the universe - Answer hydrogen and helium isotope - Answer An atom with the same number of protons and a different number of neutrons from other atoms of the same element. combustion reaction - Answer the oxidation reaction of an organic compound, in which heat is released; exothermic power - Answer the rate at which work is done work - Answer quantity of energy transferred by a force when it is applied to a body and causes that body to move in the direction of the force atomic radius - Answer average distance between the nucleus and the outermost electron Proton - Answer determines the atomic number; protons minus electrons indicates the charge Neutrons - Answer uncharged particles in the nucleus atomic mass - Answer Number of protons and neutrons atomic weight - Answer ratio of the average mass per atom of a sample Democritus - Answer Greek philosopher that said all matter is made of tiny particles called "atomos" or atoms JJ Thomson - Answer Plum pudding model Ernest Rutherford - Answer 1909-solar system model of the atom, gold foil experiment- fired negative ions at thin sheet of gold foil, discovered the atomic nucleus and proposed a nuclear model of the atom . Niels Bohr - Answer orbit model Louis de Broglie and erwin schrodigner - Answer electron cloud model Radioisotopes - Answer Isotopes that have unstable nuclei due to excess energy or undergo radioactive decay. radioactive decay - Answer A spontaneous process in which unstable nuclei lose energy by emitting radiation radioactive half-life - Answer the time it takes for half of the radioactive isotopes in a sample to decay to a new form radiation - Answer Energy that is radiated or transmitted in the form of rays or waves or particle and transfered to another body gamma rays - Answer high-energy electromagnetic waves emitted from a nucleus as it changes from an excited state to a ground energy state gamma wave radiation - Answer fast moving radiation that can cause cancer or genetic information damage by crashing into cells Electronegativity - Answer A measure of the ability of an atom in a chemical compound to attract electrons dipole - Answer a molecule that has two poles, or regions, with opposite charges polar covalent bond - Answer A covalent bond in which electrons are not shared equally Pauling scale - Answer the unit used to measure electronegativity oxidation number - Answer Positive or negative number that indicates how many electrons an atom has gained, lost, or shared to become stable Lewis diagram - Answer a diagram that illustrates chemical bonding by showing only an atom's valence electrons and its chemical symbol cathode ray - Answer a stream of electrons produced at the negative electrode (cathode) of a tube containing a gas at low pressure period - Answer horizontal row in the periodic table where atomic numbers increase from left to right photon - Answer an elementary particle thought to be the basic unit of light in the periodic table columns are numbered 1-18 for elements with similar - Answer outer electron shell configurations in the periodic table atomic radii will ______ from left to right across a peroid - Answer decrease electronegativity _______ from left to right on the periodic table - Answer increases molar mass - Answer the mass of one mole of a pure substance Charles' Law - Answer states that gases expand when they are heated Boyle's Law - Answer gases contract when pressure is applied to them; if tempurature is held constant the relationship between pressure and volume is inversely proportional