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Unit 1 ch 2
Question | Answer |
---|---|
Matter | occupies space and possesses rest mass, especially as distinct from energy. |
Element | A substance that cannot be decomposed into simpler substances |
Compound | A substance consisting of atoms or ions of two or more elements that are chemically bonded together, |
Atomic nucleus | is the small, dense region consisting of protons and neutrons at the center of an atom |
Atomic number | the number of protons in the nucleus of an atom |
Mass number | the total number of protons and neutrons in a nucleus. |
Atomic mass | the mass of an atom of a chemical element expressed in atomic mass units. |
Isotopes | Different forms of the same element with the same number of protons but different number of neutrons |
Radioactive isotope | An isotope having an unstable nucleus that decomposes spontaneously |
Energy | Capacity to cause change |
Potential energy | Energy that matter possesses Bc of its location or structure |
Electron shells | A characteristic average distance and energy level |
Valence electrons | Outer electrons |
Valence shell | Outermost electron shell |
Chemical bond | Attractions |
Covalent bond | Sharing of a pair of valence electrons by two atoms |
Molecule | Two or more atoms held together by covalent bonds |
Single bond | A pair of shared electrons |
Double bonds | O = O |
Valence | the combining power of an element |
Electronegativity | The attraction of a particular atom for the electrons of a covalent bond |
Nonpolar covalent bond | Electrons are shared equally |
Polar covalent bond | Electrons are not shared equally |
Ion | A charged atom |
Cation | Positive charged atom |
Anion | Negatively charged atom |
Ionic bond | Oppositely charged bonds |
Ionic compound | Compounds formed by ionic bonds |
Hydrogen bond | Noncovalent attraction between a hydrogen and an electronegative atom |
Chemical reactions | Making and breaking of chemical bonds, leading to changes in the composition of matter |
Polar molecule | Charge is unevenly distributed (uneven electron charge) |
Cohesion | Hydrogen bonds hold the substance together |
Adhesion | Sticking of one substance to another |
Surface tension | How hard it is to break the surface area |
Kinetic energy | Anything that moves, energy of motion |
Hydration shell | Sphere of water molecules around each dissolved ion |
Hydrophilic | Likes water |
Hydrophobic | To repel water |