Pg 130 #13-25
13. Give another term for each of these features of the periodic table.
a. Row: Period (elements with similar chemical properties)
b. Column: Group or Family (arranged based on the increasing atomic weight)
14. Give the names and symbols of two elements other than lithium in the alkali metal family.
a. Sodium (Na)
b. Potassium (K)
15. Consider the noble gas family.
a. Where are noble gases located on the periodic table:
i. The right side of the periodic table.
b. Name one physical property that noble gases share.
i. They are all in a gaseous state at room temperature.
c. Name one chemical property that noble gases share.
i. They are unreactive (or even chemically inert).
16. Given a periodic table and the formulas BeCl2 and AlN, predict the formula for a compound containing:
a. Mg and F: MgF2
b. Ga and P: GaP
17. The melting points of sodium (Na) and rubidium (Rb) are 98 oC, and 39 oC respectively. Estimate the melting point of Potassium (K).
a. 68.5oC
18. Would you expect the boiling point of chlorine to be higher or lower than that of iodine? Explain.
a. I expect the boiling point to be higher than chlorine because the atomic mass is larger and there are more protons, neutrons, and electrons in iodine, rather than chlorine.
19. Copy and complete the following table for each electrically neutral atom.
20. Using figure 2.11 (page 121) as a model, illustrate the number of protons, neutrons, and electrons in an atom of:
a. Beryllium: Protons: 4, Neutrons: 5, Electrons: 4
b. Nitrogen: Protons: 7, Neutrons: 7, Electrons: 7
c. Neon: Protons: 10, Neutrons: 10, Electrons: 10
21. A student asked to explain the formation of a lead (II) ion (Pb2+) from an electrically neutral lead atom (Pb). The student says that a lead atom must have gained two protons to make the ion. How would you correct this student’s mistaken explanation?
a. I would correct the student’s mistake by telling them that in order to make an ion, a lead atom must lose two electrons in order to make a positive ion.
22. Refer to the table provided for Question 19:
a. Calculate the mass number for each element in the table.
i. Carbon: 12, Carbon: 13, Calcium: 41, Platinum: 195, Uranium: 238
b. Which element has two isotopes in the table?
i. Carbon
23. A scientist announces the discovery of a new element. The only characteristic given in the report is the element’s mass number of 266. Is this information sufficient, by itself, to justify the claim of the discovery of the new element? Explain.
a. No, because in order for it to be an element, other information is needed, such as atomic weight, and maybe even a name and symbol for the element.
24. How does the mass of an electron compare to the masses of a proton and a neutron?
a. The mass of an electron is almost nothing compared to that of a proton or neutron.
25. How many protons and neutrons are needed for each magnesium isotope in this table?
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