Question

1. based on the concept of periodic trends, answer the following questions for these atoms: li, be, mg, na. be able to defend your answers.

a. which element has the lowest electronegativity?
b. which element has the least metallic character?
c. which element is the largest atom?

1. based on the concept of periodic trends, answer the following questions for these atoms: p, s, cl, f. be prepared to defend your answers.

a. which element has the highest electronegativity?
b. which element has the least metallic character?
c. which element has the largest ion?

1. which group tends not to form ions or react?
2. the electron configuration of calcium is 1s²2s²2p⁶3s²3p⁶4s². in its reactions, calcium tends to form the ca²⁺ ion. which electrons are lost upon ionization?

a. the 4s electrons
b. two of the 3p electrons
c. the 3s electrons
d. the 1s electrons

1. which element in period 3 has both metallic and nonmetallic properties?
2. elements in period 3 are alike in that they all have the same number of

a. protons
b. neutrons
c. electrons in the valence shell
d. occupied principal energy levels

1. as one proceeds from fluorine to astatine in group 17 the electronegativity

a. decreases and the atomic radius increases
b. decreases and the atomic radius decreases
c. increases and the atomic radius decreases
d. increases and the atomic radius increases.

Explanation:

Step1: Recall periodic - trend rules for electronegativity

Electronegativity increases across a period and decreases down a group. For Li, Be, Mg, Na: Na is the most electropositive among them as it is in Group 1 and lower in the periodic table compared to the others. So for the set Li, Be, Mg, Na, Na has the lowest electronegativity. For P, S, Cl, F, F has the highest electronegativity as it is the most electronegative element in the periodic table.

Step2: Recall periodic - trend rules for metallic character

Metallic character decreases across a period and increases down a group. For Li, Be, Mg, Na, Be has the least metallic character as it is further to the right in its period compared to Li and Na, and above Mg in the same group. For P, S, Cl, F, F has the least metallic character as it is a non - metal and is in the most non - metallic part of the periodic table among these elements.

Step3: Recall periodic - trend rules for atomic size

Atomic size increases down a group and decreases across a period. For Li, Be, Mg, Na, Na has the largest atom as it is in a lower period (Period 3) compared to Li and Be (Period 2), and although Mg is also in Period 3, Na is in Group 1 and Mg is in Group 2, so Na has a larger atomic radius. For P, S, Cl, F, P has the largest ion among them considering their anionic forms (since they tend to gain electrons), as it is in a lower period compared to S, Cl, and F.

Step4: Identify the non - reactive group

Group 18 (noble gases) tend not to form ions or react due to their stable electron configurations.

Step5: Determine electrons lost in calcium ionization

Calcium has an electron configuration of \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}\). In ionization to form \(Ca^{2 +}\), the outermost electrons are lost first, which are the 4s electrons.

Step6: Identify the element in Period 3 with both metallic and non - metallic properties

Silicon (Si) in Period 3 has both metallic and non - metallic properties and is a metalloid.

Step7: Analyze similarities among Period 3 elements

Elements in Period 3 all have the same number of occupied principal energy levels (n = 3).

Step8: Analyze trends in Group 17

As one proceeds from fluorine to astatine in Group 17, the electronegativity decreases and the atomic radius increases due to the addition of electron shells and increased shielding effect.

Answer:

1. a. Na

b. Be
c. Na

1. a. F

b. F
c. P

1. Group 18
2. a. the 4s electrons
3. Silicon (Si)
4. d. occupied principal energy levels
5. a. decreases and the atomic radius increases