Chemistry Review Sheet PDF

Chemistry Test Review An **[atom]** is a building block of matter. A **[proton]** is located in the nucleus and has a positive charge. A **[neutron]** is located in the nucleus and has a neutral charge. An **[electon]** is located in the energy levels and has a negative charge. The atomic numbe...

Chemistry Test Review An **[atom]** is a building block of matter. A **[proton]** is located in the nucleus and has a positive charge. A **[neutron]** is located in the nucleus and has a neutral charge. An **[electon]** is located in the energy levels and has a negative charge. The atomic number identifies an element. The atomic number is equal to the number of protons in an atom. The mass number of an atom is the sum of the protons and neutrons. An atom with 53 protons and 74 neutrons has an atomic number of 53. An atom with 53 protons and 74 neutrons has a mass number of 127. An atom with 53 protons and 74 neutrons is the element Iodine. The horizontal rows on the periodic table are called periods. The vertical columns on the periodic table are called families or groups. Metals are found on the left of the periodic table. Nonmetals are found on the right of the periodic table. Metalloids are found on the zig zag of the periodic table. Metals are good conductors of heat and electricity. Melas have a luster (shiny) Metals are ductile (can be made into wires) Metals are malleable (can be made into sheets) A metalloid has the properties of metals and nonmetals. Elements in the same group have similar properties because tey have the same number of valence electrons. An atom's valence electron number is the number of their family or group on the periodic table. Group 1 is called the Alkali metals. Group 2 is called the Alkaline Earth metals. Grous 3-12 are called the Transition metals. Group 13 is called the Boron Family. Croup 14 is called the Carbon Family. Group 15 is called the Nitrogen Family. Group 16 is called the Oxygen Family. Group 17 is called the Halogens. Group 18 is called the Noble Gasses. The combining of atoms of elements to form new substances is called **[chemical bonding.]** Bonding that involves a transfer of electrons is called **[ionic bonding]**. Metals combining with a nonmetal for ionic bonds. A charged atom is an ion. Atoms with 1,2,3 or 4 valuence electorons will lose electrons. Atoms with 5,6 or 7 valuence ectorongs with gain electrons. Socium (Na( will form a positive ion because elements with 1 valence electrons will lose electrons. The oxidation number of Oxygen (O) is [*O*^ − 2^]{.math.inline} The oxidation number of Aluminum (Al) is [Al^ + 3^]{.math.inline} A covalent bond is when electrons are shared, not transferred. Nonmetals combine with nonmetals with covalent bonds. Pure substance are elements or compouns like table salt and sugar. Mixtures are formed when 2 or more substances are combined. In a homogenous mixture, the parts of the mixture are evenly distributed. In a heterogenous mixture, the parts are not evenly distributed. Raisin bran is a heterogenous mixture. Milk is a homogenous mixture. Water is a compound. Gold is an element. Sand and salt form a hetogenous mixture. Iced tea is a homogenous mixture. [*H*~2~*O*]{.math.inline} has 2 hydrogen and 1 oxygen atoms. [4*CO*~2~]{.math.inline} has 1 carbon and 2 oxygen atoms. [*C*~6~*H*~12~*O*~6~]{.math.inline} has 6 Carbon, 12 hydrogen and 6 oxygen atoms. A physical change changes the appearance of a substance but not he chemical composition. (It's the same thing, it just looks different.) A chemical change forms a new substance with new properties. (A new thing was created) Melting is a physical change. Boiling is a physical change. Burning is a chemical change. Rotting is a chemical change. Rusting is a chemical change. Phase change is a physical change. A solid has tightly packed molecules. A solid has molecules that vibrate more slowly. A solid has a definite shape. A solid has a definite volume. A liquid has more spread out molecules. A liquid has molecules that are moving faster. A liquid does NOT have a definite shape. A liquid has a definite volume. A gas has very spread out molecules. A gas has molecules that move the fastest. A gas does NOT have a definite shape. A gas does NOT have a definite volume. Freezing is a phase change from liquid to solid. Melting is a phase change from solid to liquid. Vaporization is a phase change from liquid to gas. Condensation is a phase change from gas to liquid. Density is the mass per unit volume of a material. A specific material **always** has the same density regardless of its size. Density equal mass divided by volume. The density triangle has Mass on the top. The density triangle has Density and then Volume on the bottom. Water has a density of 1g/cc. Objects that have a density of less than 1 g/cc float. Objects that have a density of more than 1 g/cc sink. Objects that have a density of equal to 1 g/cc float suspend in water.