2' The representative elements In these elements the outermost s and p orbitals are only partially f

1

• 2. The representative elements- In these elements
  the outermost s and p orbitals are only partially
  filled.
• The group that the elements belongs in indicates
  the number of electrons in the outermost energy
  level.
• For example, all of Group 1A elements have only
  one electron in its outermost energy level and
  elements in 4A have four.
• The halogens, in Group 7A all have five electrons
  in the p sublevel of the outermost energy level,
  totaling 7.(2 in the s sublevel)

2

• 3. The transition metals- these are metallic
  elements characterized by addition of electrons
  to the d sublevel.
• 4. The inner transition metals- characterized by
  the addition of electrons to the f sublevel.
• A pattern emerges with increasing atomic number
  as well as electron configuration and the four
  groups can be blocked like the example on page
  395 in figure 14.5.
• Helium is the exception of the noble gases where
  it only has electrons in the s orbital. All of
  the other noble gases in Group 0 have their
  outermost electrons in the p sublevel. If you
  notice, all of the p sublevel is full with 6
  electrons.

3

• At your seat work on questions 3,4 and 5 on page
  396.

4

• Answers from page 396
• 3. Why do the elements potassium and sodium have
  similar chemical properties?
• Because they have similar electron
  configurations with the highest energy sublevel
  having only one electron.
• 4. a. transition metal (Ag)
• b. noble gas (Kr)
• c. transition metal (Cr)
• d. representative element (Si)
• 5. Cu, Cd, Au, Co These elements have partially
  filled d sublevels.

5

• TRENDS IN ATOMIC SIZE
• The radius of an atom can not be measured
  directly because of the undefined boundary set by
  the electrons.
• If atoms are in a crystalline structure, then an
  approximation of the size of the nucleus is
  calculated using a technique called X-ray
  diffraction.

6

• The group trend and periodic trend of elements
  is, that as you move down a group, the size of
  the nucleus increases.
• As you move across the period table from left to
  right, the nucleus generally decrease in size,
  even though the number of subatomic particles
  increases.

7

• IMPORTANT CONCEPT
• This is because the increasing positive charge of
  the protons draw surrounding electrons closer to
  the nucleus. As the electrons pull closer, the
  protons squeeze in tighter to each other.

8

• TRENDS IN IONIZATION ENERGY
• When an atom gains or loses an electron it
  becomes an ion.
• The energy required to overcome the attraction of
  the nuclear charge and remove an electron from a
  gaseous atom is called the ionization energy.
• The energy required to remove an electron from
  its outermost energy level is referred to as the
  first ionization energy.

9

• To remove a second electron from a charged ion is
  called the second ionization energy, and so
  forth.
• To remove one electron from a Group 1A is easy
  but to remove a second is much more difficult.

10

• From Group 2A it is easy to remove the first and
  second electron, but to remove a third and so
  forth gets increasingly more difficult.
• As you move down a group the ionization energy
  decreases because the distance between the
  electron and the positive nucleus increases.

11

• For the representative elements, as you move
  across a period, ionization energy increases
  because the greater attraction of the increasing
  positive nucleus makes it more difficult to
  remove the electron.
• How does the gaining or losing of electrons
  affect the size of an atom?

12

• Cations are smaller in size than the uncharged
  atom.
• Losing an electron in the outer energy level
  increases the attractive force of the nucleus to
  the fewer remaining electrons.
• Anions are larger than the uncharged atom because
  the effective nuclear force is decreased by the
  increase in negative charge.

13

• TRENDS IN ELECTRONEGATIVITY
• When an anion is chemically combining with a
  cation it has a certain amount of draw to take on
  an electron.
• The tendency for an atom to attract electrons is
  called electronegativity.
• Electronegativity decreases as you go down a
  group and increases as you go across a period.
• What is the only property that shows a trend of
  decreasing as you move from left to right across
  a period?
• Atomic radius

14

• AT YOUR SEAT WORK ON QUESTIONS 6 TO 9 ON PAGE 406

15

• Answers to page 406
• 6.For which of these properties does lithium have
  a larger value than potassium?
• Lithium has a higher first ionization energy and
  electronegativity than potassium.
• 7. Arrange the elements in order of decreasing
  atomic size sulfur, chlorine, aluminum, and
  sodium.
• sodium, aluminum, sulfur, chlorine
• Periodic trend

16

• 8. How does the ionic radius of a typical anion
  compare with the radius for the corresponding
  neutral atom?
• Anion is larger than the atom
• 9. Which element in each pair has the larger
  ionization energy?
• a. sodium larger than potassium because Na is
  above K in the row.
• b. phosphorus larger than magnesium because
  phosphorus is more to the right of the periodic
  table.
• END OF CHAPTER NOTES

17

• Use Figure 14.5 on page 395 write the electron
  configuration of these elements
• a. the inert gas in period 3.
• b. the element in Group 4A, period 4.
• c. the element in Group 2A, period 6.
• Note f orbitals do not fill up until you reach
  57 La on the periodic table, 5s, 5p, and 6s fill
  up before 4f prior to La for the transition
  metals.
• Answers
• Ar 1s22s22p63s23p6
• Ge 1s22s22p63s23p63d104s24p2
• Ba 1s22s22p63s23p63d104s24p64d105s25p66s2

18

• What are the symbols for all the elements with
  the following outer configuration
• a. s1
• H, Li, Na, K, Rb, Cs, Fr
• b. s2p4
• O, S, Se, Te, Po
• c. s2d10
• Zn, Cd, Hg, Uub

19

• Explain how an elements outer electron
  configuration is related to its position on the
  periodic table.
• An elements outer electron configuration places
  it in a particular column(group) of the periodic
  table.

20

• Two factors that play a role on atomic
  radius(size of the atom)
• 1. As you move across a period, the increasing
  nuclear charge(protons within the nucleus with a
  positive charge) pull the particles of an atom
  closer together. The increasing electrons are all
  increasing within the same energy level and do
  not have a balanced effect since their energy
  pull doesnt increase the way the positive charge
  increases.
• 2. The shielding effect plays a role on the
  increase as you move down a group(vertical row)
  The electrons are added in a different energy
  level and as a result are further from the
  nucleus. This results in less nuclear pull to
  center and as a result the size of the atom
  increases.