PAX RN ENTRANCE EXAM QUESTIONS AND ANSWERS 2024

ATOM (physics and chemistry) the smallest component of an element having the chemical properties of the element MATTER Anything that has mass and occupies space. SUBSTANCE Any material all samples of which have the same composition and properties ( a mixture is not a substance) ELEMENT Identified by its symbol and its atomic number ATOMIC NUMBER Number of protons in the nucleus of an atom MASS NUMBER Sum of the number of protons and neutrons in the nucleus of an atom ISOTOPE Atoms of the same element (with the same number of protons) that contain a different number of neutrons. ATOMIC MASS The weighted average of the mass numbers of all naturally occurring isotopes of the element. ION A charged atom PROTON A positively charged particle in the nucleus of an atom. CATION A positively charged ion ANION A negatively charged ion VALENCE ELECTRON Electrons on the outermost energy level of an atom PERIODIC TABLE A table that shows the elements, their atomic number, symbol, and average atomic mass; elements with similar chemical properties are grouped together. PERIOD A horizontal row of elements in the periodic table GROUP A vertical column of elements in the periodic table; elements in a group share chemical properties. NEUTRON A subatomic particle that has no charge and that is found in the nucleus of an atom ELECTRON Carry a negative charge and are found outside the nucleus and arranged according to their energy level METAL Elements that are good conductors of heat and electric current. METALLIOD an element that has properties of both metals and nonmetals NONMETAL Elements that are poor conductors of heat and electric current NOBLE GAS Elements in group 8A of the periodic table. Have no charge and are gases under normal conditions. (Helium, Neon, Argon, Krypton, Xenon, Radon) RADIO-ISOTOPES Isotopes that are radioactive OCTET RULE Atoms react by gaining or losing electrons so as to acquire the stable electron structure of a noble gas, usually eight valence electrons. IONIC BOND Attraction formed between oppositely charged ions in an ionic compound. LEWIS ELECTRON DOT DIAGRAM the representation of an atom, ion or molecule, in which the element symbols stand for the nucleus and all inner level electrons while dots stand for outer level electrons COVALENT BOND A chemical bond that involves sharing a pair of electrons between atoms in a molecule POLAR COVALENT BOND Two different atoms share electrons unequally, the electrons being held closer to one atom than the other NONPOLAR COVALENT BOND A covalent bond with equal sharing of electrons. DIPOLE A molecule that is polar (has one side that is negatively charged and another that is positively charged) ELEMENT Simple substance made up of one type of atom COMPOUND A substance made up of two or more different atoms bonded together GAS A state of matter with no definite shape or volume LIQUID A state of matter that has no definite shape but has a definite volume SOLID A form of matter that has a definite shape and volume MELTING The process that takes solid to liquid EVAPORATION The change of a liquid to a gas VAPOR PRESSURE The pressure exerted by a vapor over a liquid. CONDENSATION Gas to Liquid FREEZING Liquid to Solid SUBLIMATION a change directly from the solid to the gaseous state without becoming liquid HOMOGENEOUS MIXTURE A mixture in which the composition is uniform throughout FILTRATION A process that separates materials based on the size of their particles SOLVENT Substance that does the dissolving TINCTURE A solution in which alcohol is the solvent CHROMATOGRAPHY A technique that is used to separate the components of a mixture based on the tendency of each component to travel or be drawn across the surface of another material. HETEROGENEOUS MIXTURE A mixture where the composition varies. For example, a box of granola cereal. EMULSION A liquid dispersed in another liquid in which it is not soluble SOLUBILITY A measure of how much solute can dissolve in a given solvent at a given temperature. DISTILLATION A process that separates the substances in a solution based on their boiling points CHEMICAL CHANGE A change that occurs when one or more substances change into entirely new substances with different properties. PHYSICAL CHANGE A change in a substance that does not involve a change in the identity of the substance