Final Buzzer This is practice for the Final

Final Buzzer This is practice for the Final covering most topics.

3 “nucleon” refers collectively to the particles in the nucleus of an atom… the protons AND the neutrons

2 Remember protons and neutrons each have a weight of about 1 u whereas electrons are virtually weightless in comparison, having a mass of about 1/2000 of an atomic mass unit.

4 The mass of an atom is contained in the nucleus and is the sum of the number of protons and neutrons.

1 Ditto the previous slide’s answer! Remember Rutherford’s experiment!!! (Gold foil…. )

4 Yup, like the last two said…

1 Atomic number is determined by the number of PROTONS!!!

1 “Nuclear charge” is the charge a nucleus has due to the number of positively charged protons. So…look up the atomic number of the element and you have it. Easy as that! In this case, Fe is atomic number 26.

1 Saying “ 40 nucleons” is like saying the atomic mass is 40. (Remember: atomic mass is the sum of the number of protons and electrons. ) If the number of neutrons is 22, then by subtraction (40 – 22) the number of protons must be 18.

1 If the word “atom” is used, then the number of protons = the number of electrons, therefore the answer is 18 in this case, since atomic number 18 means 18 protons.

4 So this question is testing to see if you know that “conductivity” for solids is a property only of metallic elements. Sulfur and nitrogen are nonmetals, and neon is a noble gas. What are other metallic properties? Hmmm…. Ductility, malleability, high density, have luster

4 “Most active” means most reactive. Remember our lab with Na, Li, K, Mg, and Ca, plus the video footage of Cs and Rb in a tub of water…. Remember the most Kaboom-a-licious metals were the lowest ones in Group 1…

2 Metals are conductors…the other properties describe nonmetals

3 Think about the one nonmetal element everyone has seen… charcoal or graphite (both are carbon). The other properties are those of metals.

2 Lookin’ for a …. Nonmetal. Yep. OR Hmmm…. Which answer is not like the other? (3 choices are metals, 1 is not…)

4 “Monatomic” means “one atom” in the formula. Therefore, this question is a “which one is a noble gas” question because noble gases do not need to bond or pair up to become stable. Already being born with 8 ‘lil electrons of its own makes an atom stable… (Hopefully you realize Group 18 is the noble gas family!)

2 I think if you miss this one…. You should flog yourself silly.

3 Remember metalloids (semi-metals) have some properties of metals and some of nonmetals. They are obviously confused elements. They are confused because they have 3 or 4 or 5 valence electrons, so they sometimes lose electrons in bonding (a metallic thing to do) and sometimes share them (what nonmetals do). There are 7 examples: B, Si, Ge, As, Sb, Te, and Po. Remember the stair-step thing on the Periodic Table!

2 Always answer this type of question by finding an element in the same group (column). They have similar properties due to having the same number of valence electrons!

3 Refer to the answer for question #17.

3 Groups are columns (up and down) – 18 of them Periods are rows (left to right) – 7 of them So, Group 2 Period 7 is “Ra”. Then, to figure out what “Ra” is, use Table S to find the symbol-name match for “Ra”.

1 • Elements with 5 valence electrons are always found in Group 15, which is sometimes pronounced “five-teen” by chemistry teachers to sort of reinforce this essential awareness…

2 • “Principal energy level” is just a fancy way of saying “energy level. ” So, carbon keeps its valence electrons in energy level 2. (Carbon has 6 electrons, distributed as “ 24”. Therefore, it has 4 valence electrons in the second energy level. )

2 • As you go from the top to the bottom in a group, they all have the same number of valence electrons (last number in electron configuration). The elements further down have more energy levels. For example: Be 2 -2 Mg 2 -8 -2 Ca 2 -8 -8 -2 AND SO ON…

3 • Boron is “B” on the periodic table. It’s element number 5 and has an electron configuration of 2 -3. Remember the valence electrons are in the outermost energy level, and boron has 3 in its outermost energy level.

4 Potassium (K – use Table S if you need to!) has an electron configuration of 2 -8 -8 -1, or 19 total electrons. When it becomes the K+1 ion, it loses its one valence electron. It now has 18 electrons (2 -8 -8) like the noble gas Argon (Ar). The answer is Argon

3 Take it apart … • Oxygen always is atomic number 8, so 8 protons. • Oxygen– 18 is the isotope of oxygen with a mass of 18. It therefore has 10 neutrons (18 -8 = 10) • Since it is an O-2 ion, it has its original 8 electrons PLUS the two it gained, so 10 electrons.

4 • Oxide ion has gained 2 electrons to become like neon, 2 -8 (it was 2 -6 as an atom, and gains two electrons in bonding with another element to become 2 -8).

4 • Remember the only naturally “stable” elements (unreactive, no need to gain or lose electrons) are the noble gases…. GROUP 18!!

My favorite teacher is Mrs. __ong

LONG That’s gotta be the easiest question in this thing…. hope you got it right ; -)

1 • “Similar properties”…. Tip off for “I’m looking on the periodic table for a groupie of silicon. ” Ge qualifies.

3 Well, if a question like this is on the mid-year assessment, just stand right up in class and say “YAHOO!!” This one is just as easy as go to the Periodic Table and read the electron configurations under F and Cl!!

2 Remember that the most metallic elements are at the bottom of a group and the most nonmetallic are at the top. The essence of being metallic is EASILY losing electrons. Elements that keep their electrons the furthest out from the nucleus lose them the easiest.

3 Choice 1 is NOT the answer. We will discuss electronegativity more in the second semester. However, if you want to know, electronegativity is sometimes thought of as wanting electrons. Nonmetals have higher values because they more likely to gain/take electrons in bonding and metals will lose electrons (and therefore have low electronegativity values). These values are on Table S! The only correct choice is that as you go from left to right in a row (period), the atomic number (and therefore number of protons) increases.

1 Compounds are ALWAYS homogeneous, whereas mixtures could be either homogeneous or heterogeneous. Compounds could have 2 components (water has H and O in it) or have 3 components (Na. OH is composed of 3 elements). So could mixtures…

4 • The word “substance” always implies a PURE sample. The only types of pure substances are elements and compounds!!!

2 This is the definition of “element. ”

3 Well, let’s see…a pair of elements turns into a compound, which would be a NEW SUBSTANCE = CHEMICAL CHANGE!!!!!!!!!

Mrs. Long’s maiden name is “Hooker. ” Mrs. Long’s mom became a “Hooker” when she married Mrs. Long’s dad. True story.

You should take a little break… go get a snack now, but make sure to come back for more fun and excitement!!

4 Do this: Mass # of atoms Ca: 40. 0 g x 3 = 120 g P: 31. 0 g x 2 = 62 g O: 16. 0 g x 8 = 128 g Adds up to: 310 g/1 mole (molar mass)

4 • Same technique as in Question #38.

4 Determine the molar mass of each using the periodic table masses and the formulas: • H 2 O 2 = 34 g/mole • NO • CF 4 • I 2 = 30 g/mole = 88 g/mole = 254 g/mole

4 • One mole of H 2 has a mass of 2 g. • So, 2 moles would have a mass of 4. 0 g.

4 S: 32. 0 g x 1 = 32. 0 g O: 16. 0 g x 2 = 32. 0 g Molar mass=64. 0 g/1 mole 64. 0 g = x 1 mole 0. 75 mole x = (64. 0)(0. 75) = 48. 0 g

2 • It might help when seeing water to think of it as “HOH” when balancing….

2 • I would start by noticing the oxygen is not balanced. So, when you factor use 5 O 2 AND 2 N 2 O 5. This then forces a 2 N 2.

1 • My advice would be to start by balancing the Cl. The coefficients, when done, become 3, 2, 1, and 3 when put in place from left to right.

4 We are comparing C 4 H 10 and O 2… • Remember: A balanced equation is a “recipe” written in moles and can be scaled up or down in proportion. Their coefficients are 2 and 13, so: 5 mol C 4 H 10 13 mol O 2 = 32. 5 mol O 2 2 mol C 4 H 10

4 • Notice one mole of Na 2 Cr. O 4 produces 2 moles of Na. Cl. • So, 2 moles of sodium chromate will have to make 4 moles of sodium chloride!

1 • 2 moles of C 2 H 2 requires 5 moles of O 2 • So, 1 mole of C 2 H 2 requires 2. 5 moles of O 2 (you could set up a t-chart to prove this)

Mrs. Long has seen which musical group/artist the most? (1) Dave Matthews Band (2) John Mayer (3) Goo Dolls (4) Guster

2 Mrs. Long has seen John Mayer 6 (or 7…) times! (DMB three times, the “Goos” once, and Guster twice)

2 • Just gotta know it! A metal with a nonmetal forms ionic compounds… metals have just 1, 2 or maybe 3 valence electrons and need to lose them to be like noble gases. Nonmetals have 5, 6, or 7 and therefore gain. So, metals will TRANSFER electrons to nonmetals to form ions (positive metal ions and negative nonmetal ions).

4 • Sharing electrons is a feature of molecular (covalent) compounds. Look for the “nonmetal/nonmetal” combo in the formulas.

1 • Same as question #51. • DO NOT FORGET: H is a nonmetal even though it is found on the left side of the Periodic Table!

2 • Again…you should be a pro by now!

4 • Remember PE diagrams (exo- and endothermic ones) • “Bond” energy is stored energy. • Example: A battery stores chemical energy (bond energy) until the reaction that happens inside it is allowed to happen when plugging the battery in.

2 • “Average Kinetic energy” = temperature…. • GOTTA KNOW THAT!

3 • Greatest increase in temperature…

3 • Again…

1 • A change of 1 degree on the Celsius scale is also a 1 degree change on the Kelvin scale. • So… a 20 degree change on one scale is also a 20 degree change in the other… • You COULD convert the temperatures using the equation on Table T, but that’s the long way to go about answering the question.

1 • Time to use Table T!! Using the conversion equation, the Kelvin temperature is always 273 degrees HIGHER than its Celsius equivalent.

3 • Same idea as #59.

4 • Think of blowing up a balloon. The air you blow in there takes the shape and fills up the whole balloon.

3 • “regular geometric pattern” is like screaming “PICK THE SOLID”!!

3 • Since it was heated originally in the solid state and then the temperature leveled off at 25 degrees, it must be melting at 25 degrees!

1 • Sublimation = changing from solid directly to gas (skipping the liquid state)… • KNOW IT

1 • Distilled water is water that has been boiled off and recondensed in another pot, thus removing all impurities. The other 3 choices are all mixtures of water and some other stuff (rainwater has pollutants mixed in).

3 The more moles per liter, the more concentrated. 1) 1 mole/1 liter = 1 Molar 2) 2 moles/ 3 liters = 0. 67 Molar 3) 6 moles/4 Liters = 1. 5 M 4) 4 moles / 8 Liters = 0. 50 M (Molarity equation on Table T!)

2 • M = 4 moles Na. OH / 2 Liters = 2. 0 Molar • This is Unit 6 info…. if you don’t know it…. YIKES!!!!!

3 Collisions between particles are always happening, but reactions are not always happening. Effective collisions must be ones that occur with high energy and must be correctly oriented in order to break the bonds in the reactants, thereby ACTIVATING them on their way to forming products.

4 • As temperature increases, the molecules move faster. They are therefore colliding harder and more often as a result.

2 • Higher concentration means more particles are present. Therefore, more collisions will happen per unit of time and the rate will increase.

2 • More surface area means more of the particles are exposed to collisions from the other type of reactant particles, so the rate increases.

72. 2

2 • Solid gas means more particle motion, or KE, exists in the products. So, the entropy of the system increases! (Also, entropy is often remembered as a degree of “disorder”)

73. 2

2 • Gas Liquid means the particles in the products are more organized, have less particle motion, and therefore less particle KE

74. If a reaction is exothermic, then it 1. 2. 3. 4. Releases heat and would show “heat” in its equation as a reactant. Releases heat and would show “heat” in its equation as a product. Absorbs heat and would show “heat” in its equation as a reactant. Absorbs heat and would show “heat” in its equation as a product.

2 • Exothermic … “exo-” means “exit, ” so heat is “released” in exothermic reactions This is shown as Heat Energy being written as a product: A + B C + D + Heat Energy

75. What is the oxidation number of the Cl atom in KCl. O? 1. +1 2. +3 3. +5 4. -1

1 • K has to be +1 and O is -2. Cl has options. All of the numbers have to add up to zero. So, to figure out Cl: K Cl O (+1) + (x) + (-2) = 0 x -1 = 0 x = +1

76. 2

4 • Use a set up like in #75.

77. 2

4 • Again…

78. The gain of electrons is defined as 1. Longification 2. Rushification 3. Oxidation 4. Reduction

4 Three really helpful things to remember: • “LEO says GER. ” (Losing Electrons is Oxidation and Gaining Electrons is Reduction) OR • OIL RIG (Oxidation is Losing, Reduction is Gaining) AND • “Reduction is reduction (of charge value). ”

79. 2

4 • If you know “reduction is reduction (of charge value)” then oxidation must mean charge value (oxidation number) is increasing. • Oxidation occurs by losing electrons (LEO)

80. 2

1 • Assign oxidation numbers to all elements and then use thinking like in Q #78 – 79. • YOU CAN NEVER LOSE/GAIN MASS!! THIS VIOLATES THE LAW OF CONSERVATION OF MASS!!