Electron Configuration And Periodic Properties Practice problems Electron Configuration And Periodic Properties

Practice Problem #1 Of the elements Li, O, C, and F, identify the one with the largest atomic radius and the one with the smallest radius. Atomic radius decreases across a period due to increasing nuclear charge. Li has the largest atomic radius – it is a group 1 element (i.e., furthest to the left in the period F has the smallest atomic radius – it is furthest to the right in the period, has the highest nuclear charge.

Practice Problem #2 Of the elements Br, At, F, I and Cl, identify the one with the largest atomic radius and the one with the smallest radius. Atomic radius increases down a group due to the outer electrons filling orbitals in higher main energy levels further from the nucleus. F has smallest atomic radius (at the top of the group) At has largest atomic radius (at the bottom of the group)

Practice Problem #3 What is ionization energy? Ionization energy is the energy required to remove one electron from a neutral atom of an element. A + energy A+ + e-

Practice Problem #4 What is an ion? What is ionization? An ion is a charged atom or a group of atoms with a charge. The charge can be positive or negative. Ionization is any process that results in the formation of an ion.

Practice Problem #5 What are second, third, etc. ionization energies? The removal of an electron from a neutral atom is the first ionization energy. The removal of additional electrons from a positive ion is the second ionization energy, third ionization energy, etc. The ionization energy increases for each successive ionization because the electron feels an increasingly stronger nuclear charge.

Practice Problem #6a Q: 3s23p5 R: 3s1 T: 5s24d105p5 X: 5s24d105p1 What is the block and location of each? Q: p block, group 17; period 3 R: s block, group 1, period 3 T: p block, group 17, period 5 X: p block, group 13, period 5

Practice Problem #6b Q: 3s23p5 R: 3s1 T: 5s24d105p5 X: 5s24d105p1 Which elements are in the same period? Q & R in same period; T&X in same period Which elements are in the same group? Q&T in same group

Practice Problem #6c Q: 3s23p5 R: 3s1 T: 5s24d105p5 X: 5s24d105p1 Which one has the highest first ionization energy? Highest first ionization energy: Q (furthest to the top right of periodic table) Which one has the lowest first ionization energy? Lowest first ionization energy: R (alkali metal, have low ionization energies.

Practice Problem #6d Q: 3s23p5 R: 3s1 T: 5s24d105p5 X: 5s24d105p1 Which would you expect to have the highest second ionization energy? After the first ionization, R attains an electron configuration like a noble gas. It would take a lot of energy to remove a second electron. The other elements still have electrons in their outmost energy level, so it would not take as much energy to remove a second electron from those elements.

Practice Problem #7 Define valence electrons: Valence electrons are the electrons that are available to be lost, gained, or shared in the formation of a chemical compound.

Practice Problem #8 In which shells are the valence electrons found and why are they important? Valence electrons are found in the highest occupied energy level. These are the electrons that are involved in chemical bonding.

Practice Problem #9 Among the main group elements, what is the relationship between the group number and the number of valence electrons among group members? Group 1: ns1 1 valence electron (same as group #) Group 2: ns2 2 v.e. (same as group #) Group 13: ns2np1 3 v.e. (group # -10) Group 14: ns2np2 4 v.e. (group # - 10) Etc.

Practice Problem #9 In general, how do the periodic properties of the d-block elements compare with those of the main group elements? Atomic radii – decreases across period but the decrease is less than in main group  Ionization energies – different from main group elements in that energies increase going down a group because valence electrons in s sublevel are less shielded  Electronegativity – have the lowest electronegativity values, aside from Groups 1 and 2; but do tend to follow trend that electronegativity increases as radii decrease.