Chapter 3

Explain why Rutherford expected all alpha particles to go through the gold foil undisturbed.

(a) The elements in group IA (1) are called (b) The elements in group IIA (2) are called (c) The elements in group VIIA(17) are called (d) The elements in group VIIIA (18) are called

Use Dalton's hook atomic models to sketch a molecule of \(\mathrm{H}_{2} \mathrm{~S}\).

Write the full atomic symbol for each isotope: (a) 8 protons, 9 neutrons (b) Atomic number 50 , mass number 119 (c) 12 neutrons, atomic number 11 (d) 28 protons, mass number 58 (e) 81 neutrons, symbol Ba

Complete the following statements: (a) The nucleus contains the charged particles in the atom. (b) The particles in the nucleus are the and (c) Almost all of the mass of an atom is contained in the (d) The two particles whose charges cancel to make an atom neutral are and

How do metals and nonmetals differ with regard to their tendency to gain or lose electrons? With their tendency to form cations or anions?

Calcium reacts with fluorine to form the compound \(\mathrm{CaF}_{2}\). In the reaction, each atom of one of the elements loses two electrons, and each atom of the other element gains one electron. (a) Atoms of which element gain electrons? (b) Atoms of which element lose electrons? (c) What is the charge on the atoms that gain one electron? (d) What is the charge on the atoms that lose two electrons? (e) Write the full atomic symbol, including charges, for each element. Give Ca 20 neutrons and F 10 neutrons.

Use the elements lithium, potassium, and sodium to explain what is meant by chemical periodicity.

There are three isotopes of hydrogen-protium, deuterium, and tritium. Protium contains one proton and no neutrons. Deuterium contains one more neutron than protium, and tritium contains one more neutron than deuterium. For each isotope, give the atomic number, mass number, number of protons/ neutrons/electrons, and full atomic symbol.

Given that one measure of metallic character is the tendency to lose electrons, arrange \(\mathrm{Cs}, \mathrm{Be}, \mathrm{Li}, \mathrm{Ne}\), Na in order of increasing metallic character.

For each pair, indicate which atom loses an electron more easily: (a) \(\mathrm{Na}\) or \(\mathrm{K}\) (b) Na or Al (c) \(\mathrm{Rb}\) or \(\mathrm{Ca}\) (d) \(\mathrm{S}\) or \(\mathrm{Cl}\) (e) Br or Kr

Explain the difference between mass number and atomic mass.

Naturally occurring copper, \(\mathrm{Cu}\), is composed of two isotopes. The isotope copper-63 is \(69.17 \%\) of naturally occurring copper and has an atomic mass of \(62.94\) amu. The isotope copper- 65 has an atomic mass of \(64.93\) amu. (a) What percent of naturally occurring copper is copper-65? (b) Calculate the atomic mass of naturally occurring copper.

Explain why an alternative name for the vertical columns in the periodic table is families.

Explain why the first and second statements of Dalton's atomic theory are not exactly true.

Write the name of each element: (a) \(\mathrm{Be}\) (b) \(\mathrm{Mg}\) (c) \(\mathrm{Fe}\) (d) \(S\) (e) \(\mathrm{Ar}\) (f) \(\mathrm{Cu}\)

Although not discussed until the next chapter, what process do you think chemists mean by an atom's second ionization energy?

Regarding problem \(3.137\), do you think an atom's second ionization energy would be smaller, the same, or larger than its first ionization energy? Do you think the second ionization energy for an atom would ever be less than the first? Explain.

Postulate a reason why the first ionization energy increases as we progress from left to right across a period.

Atom A has 35 protons and 44 neutrons in its nucleus. Atom \(\mathrm{B}\) has 35 protons and 46 neutrons in its nucleus. Should we expect similar or different chemical properties for these atoms? Explain.

The first ionization energy is the minimum energy required to remove an electron from a neutral atom. Upon escape from the atom, how would the now free electron differ if you had used more energy than the minimum first ionization energy as compared to using the exact first ionization energy?

Suppose \(12.0 \mathrm{~g}\) of silicon (Si) reacts with \(70.0 \mathrm{~g}\) of oxygen \(\left(\mathrm{O}_{2}\right)\) to give \(25.6 \mathrm{~g}\) of the compound silicon dioxide \(\left(\mathrm{SiO}_{2}\right) .\) In the process, all the silicon gets used up, but some oxygen is left over. (a) For the law of conservation of matter to be obeyed, how much oxygen is unused? (b) What is the percent \(\mathrm{Si}\) in \(\mathrm{SiO}_{2} ?\) (c) What is the percent \(\mathrm{O}\) in \(\mathrm{SiO}_{2}\) ?

An electromagnet bends the path of the fast moving ions in a mass spectrometer so they can reach the detector. The strength of an electromagnets magnetic field depends on the how much voltage is being fed to the magnet. How does a mass spectrometer measure the mass of a single atom?

Suppose two ions have been accelerated down a mass spectrometer, one of light mass and one of heavy mass. Which one do you think will take more voltage to the electromagnet to make it reach the detector? Explain. (Hint: Think about moving a chair versus a piano.)

How can a mass spectrometer determine if a rack sample is from Earth or from some extraterrestrial source?