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2nd Nine Weeks Vocab
Term | Definition |
---|---|
atom | small particle that is the building block |
nucleus | The central core of an atom containing protons and neutrons. |
proton | A positively charged subatomic particle found in the nucleus of an atom. |
neutron | A neutral (uncharged) subatomic particle found in the nucleus of an atom. |
Element | Substance that consists of just one type of matter |
atomic number | The number of protons in an atom's nucleus, which determines the element's identity |
atomic mass | The total mass of an atom, calculated by adding the number of protons and neutrons. |
electron cloud | The region surrounding the nucleus where electrons are most likely to be found. |
electron shell | A specific energy level or orbit where electrons are located. |
valence electron | Electrons in the outermost shell of an atom that are involved in chemical reactions. |
compound | : Substance containing atoms of two or more different elements chemically bonded together |
molecule | A group of atoms bonded together, representing the smallest unit of a compound |
ion | An atom or group of atoms that has gained or lost electrons, resulting in a charge. |
periodic table | A chart that organizes elements based on their atomic number, properties, and electron configuration |
chemical symbol | A one- or two-letter representation of an element (e.g., H for hydrogen, O for oxygen). |
chemical formula | A combination of chemical symbols and numbers that represents a compound's composition. |
isotope | Different forms of an element with the same number of protons but different numbers of neutrons. |
bohr model | A simplified model of the atom that depicts electrons orbiting the nucleus in specific energy levels. |
lewis dot structure | A diagram that represents the arrangement of valence electrons in an atom or ion. |
group | column on the periodic table |
period | row on the periodic table |
periodic table | chart of the elements arranged in rows and columns according to the elements' physical and chemical properties |
alkali metal | element in group 1 on the periodic table |
alkaline earth metal | element in group 2 on the periodic table |
ductility | ability of a substance to be pulled into thin wires |
luster | ability of a metal to reflect light |
metal | generally shiny element; easily pulled into wires or hammered into thin sheets; a good conductor of electricity and thermal energy |
transition element | element in groups 3-12 on the periodic table |
halogen | element in group 17 on the periodic table |
metalloid | element with physical and chemical properties of metals on the periodic table |
noble gas | element in group 18 on the periodic table |
nonmetal | element that has no metallic properties |
semiconductor | material that conducts electricity at high temperatures but not at low temperatures |
metallic bond | the type of chemical bond between atoms in a metallic element |
ionic bond | a bond between a metal and a nonmetal |
covalent bond | a bond between a nonmetal and a nonmetal |
electronegativity | the degree to which an element tends to gain electrons and form negative ions in chemical reactions |
Lewis dot diagram | representation of the valence electrons of an atom that uses dots around the symbol of an element. The number of dots equals the number of valence electrons in that atom |
ions | an atom or molecule with a net electric charge due to the loss or gain of one or more electrons |
cation | a positively charged ion; formed when a metal loses an electron |
anion | a negatively charged ion; formed when a nonmetal gains an electron |
octet rule | -atoms of low atomic number tend to combine in such a way that they each have eight electrons in their valence shells, giving them the same electronic configuration as a noble gas |