PERIODIC TRENDS

On Tuesday we spent time going over the work sheets, or test review- and here are the answers.

Section 6.3

1. Atomic radii cannot be measured directly because the electron cloud surrounding the nucleus does not have a clearly defined
c. Outer edge

2. Which diagram best represents the group and period trends in atomic radii in the periodic table?
c. diagram c

3. The general trend in the radius of an atom moving down a group is partially accounted for by the
d. Shielding of the outer electrons by inner electrons.

4. A------ is an atom, or bonded group of atoms, that has a positive or negative charge.
b. Ion

5. An atom becomes negatively charged by
a. Gaining an electron

6. Which diagram best represents the relationship between the diameter of a sodium atom and the diameter of a positive sodium ion?
a. Diagram a

7. What is ionization energy?
Energy required to remove an electron from a gaseous form

8. Explain why an atom with a high ionization-energy value is not likely to form a positive ion?
A high ionization-energy value indicates that the atom has a strong hold on it’s electron and is not likely to lost an outer electron and form a positive ion

9. What is the period trend in the first ionization energies? Why?
The 1st ionization energies generally increases as you move left to right across a period. The increased nuclear change of each successive element produces and increased hold on the valence electrons.

10. What is the group trend in the first ionization energies? Why?
The 1st ionization energies generally decrease as you move down a group because atomic size increases down a graph, the valence electrons are far then from the nucleus and there for less strongly attached to the nucleus as a result, less energy is required to remove the valence electron.

11. State the Octet rule.
Atoms tend to gain, lose, or share electron to a quire a full set of eight valence electron.

12. What does the electro negativity of an element indicate?
Its atom’s ability to attract electron in a chemical bond
13. What are the period and group trends in electronegativities?
Increases left to right across a period and decreased as you move down a group.