Atoms and Periodic Table Review What is the charge of the nucleus and what is it made of? The charge of the nucleus is positive. It is made up of protons and neutrons. Protons carry the positive charge. What is the charge of an electron? An electron has a charge of -1 Why do most atoms have no overall charge? The positive charge of the protons is negated by the negative charge of the electrons.

Atoms and Periodic Table Review How do electrons behave, according to Bohr? Like planets orbiting the Sun. What about an electron can we not determine, according to the modern theory? We cannot determine both its position and its velocity. Elements on the periodic table are arranged in order of increasing…. Protons

Atoms and Periodic Table Review What is the difference between a family and a period on the periodic table? What changes in either case? A period is marked by the filling of energy levels with the new period starting after all shells have been filled in the previous energy level. A family is grouped by valence electrons. Each member of a family will react in a chemically similar way. What four different orbitals do we currently know about? S, P, D and F

Atoms and Periodic Table Review What is the same about all elements in the same group? They have the same # of valence electrons. What do valence electrons determine? How do you find the valence electrons for a particular atom? An atom’s chemical reactivity What is ionization? When an atom has a different number of protons than electrons. This will result in a net charge for the atom.

Atoms and Periodic Table Review Why don’t ions react like their corresponding atoms? They have different numbers of valence electrons. What does an atom’s atomic number tell us? What does the mass number tell us? The atom’s atomic number tells us the number of protons in the atom. The atom’s atomic mass tells us the combined number of protons and neutrons. 

Atoms and Periodic Table Review Where are alkali metals located on the periodic table? Know the properties of the families on the periodic table. Alkali metals are located in group 1 – they are extremely reactive Alkaline Earth metals are in group 2 – They are very reactive Transition metals are in groups 3-12 – mostly shiny and malleable. Still reactive but not as much as groups 1-2 Nonmetals are in groups 13-16 above the “staircase” Mostly gasses and non-metal solids. Halogens are in group 17 – extremely reactive. The opposite of alkali metals in group 1 Nobel gasses are in group 18 – non-reactive. All valence shells are filled.

Atoms and Periodic Table Review Why are the noble gases also called inert? They do not react with other chemicals How do we balance chemical equations? What do we add? We add coefficients to the reactants and the products until the number of each element's atoms on the reactants side is equal to the number of each element's atoms on the products side. What substances are to the left of the arrow in a chemical equation? To the right? The reactants are on the left side of the arrow. The products are on the right side of the arrow.

Atoms and Periodic Table Review What does the arrow mean in a chemical reaction? The arrow shows the direction of the chemical reaction. It can be stated in words as “reacts to produce” or “reacts to yield” How do we know how many elements are in a compound? We count the chemical symbols When is a chemical reaction balanced? When the same number of each elements atoms exist on each side of the reaction.

Atoms and Periodic Table Review When is it okay to change the coefficients? When is it okay to change the subscripts? You may change coefficients when a reaction is unbalanced. You may NEVER change subscripts as this changes the reactants or products of the reaction. What is a chemical reaction? A chemical reaction has 3 properties The reactants change into products There are new substances with new chemical properties formed The law of conservation of mass applies.

Atoms and Periodic Table Review Draw a nitrogen-14 atom and label each part with the correct number of protons, neutrons and electrons in the appropriate spots.

Atoms and Periodic Table Review What must the total mass of the products equal? The total mass of the reactants In each of the following, list which elements are present and how many of each element are present: F2 H2SO4 NH4Cl 4 Ca3(PO4)2 2Flourine 2 Hydrogen 1 Nitrogen 12 Calcium 1 Sulfur 4 Hydrogen 8 Phosphorus 4 Oxygen 1 Chlorine 32 Oxygen

Atoms and Periodic Table Review For the last problem, which of the numbers were coefficients, and which were subscripts? The preceding 4 is a coefficient. The 3,4 and 2 are subscripts What is the Law of Conservation of Mass and what does it tell us? Mass cannot be created or destroyed. It tells us that the number of each element's atoms on the reactant side of the chemical reaction must be the same as on the products side of the reaction.

Atoms and Periodic Table Review Balance the following equations: KOH + HCl  KCl + H2O Pb(NO3)2 + 2KI  2KNO3 + PbI2 2NaHCO3  H2O + CO2 + Na2CO3 2NaCl + H2SO4  Na2SO4 + 2HCl

Atoms and Periodic Table Review Explain why atoms have no electric charge even though they are made up of charged particles. The positive charge in the protons is offset by the negative charge in the electrons. A “neutral” atom has equal numbers of protons and electrons.

Atoms and Periodic Table Review

Atoms and Periodic Table Review