Question

1. which statement about li is true when it forms an ion?

a. it gains one electron
b. it loses two electrons
c. it turns into a tiny electron manager
d. it loses one electron

1. electronegativity is a measure of an atoms ability to:

a. attract electrons in a chemical bond
b. lose electrons to form a cation
c. absorb light and release it
d. perfectly balance a spoon

1. which element would have the lowest electronegativity?

a. barium (ba)
b. oxygen (o)
c. chlorine (cl)
d. nitrogen (n)

1. a neutral atom of ca (calcium) has an oxidation number of zero. when it forms an ion, its oxidation number bec

a. 2+
b. 2-
c. 1+
d. 1-

1. which element has the electron configuration: 1s²2s²2p⁶3s²3p⁶4s²?

a. element uhm
b. iodine (i)
c. xenon (xe)
d. calcium (ca)

1. which type of emr has the shortest wavelength and highest energy?

a. gamma rays
b. radio waves
c. visible light
d. infrared waves

1. the valence shell of an atom is defined as the:

a. 1s orbital
b. outermost energy level
c. nucleus of the atom
d. place where electrons store their tiny suitcases

1. a nonpolar covalent bond forms when the δen is:

a. less than 0.5 or very small
b. very large
c. exactly 42
d. moderate

1. the noble gas core in the electron configuration ar4s²3d¹⁰4p² represents the electron configuration of:

a. neon (ne)
b. krypton (kr)
c. argon (ar)
d. germanium (ge)

1. aluminum will form an ion with what oxidation number?

a. 3+
b. 3-
c. 13+
d. 13-

1. which of the following elements has the greatest electronegativity?

a. oxygen (o)
b. sulfur (s)
c. helium (he)
d. cesium (cs)

Explanation:

• Question 14: Lithium (Li) has an atomic number of 3. Its electron configuration is \(1s^{2}2s^{1}\). To achieve a stable electron configuration (similar to the noble gas helium), it loses one electron.
• Question 15: Electronegativity is defined as the ability of an atom in a chemical bond to attract electrons.
• Question 16: Electronegativity increases across a period and decreases down a group. Barium (Ba) is in Group 2 and Period 6, while oxygen (O) is in Group 16 and Period 2, chlorine (Cl) is in Group 17 and Period 3, and nitrogen (N) is in Group 15 and Period 2. So Ba has the lowest electronegativity.
• Question 17: Calcium (Ca) has an atomic number of 20. Its electron configuration is \([Ar]4s^{2}\). To achieve a stable electron configuration (similar to argon), it loses two electrons, so its oxidation number becomes \(2+\).
• Question 18: The electron configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}\) has a total of \(2 + 2+6 + 2+6 + 2=18\) electrons. Calcium (Ca) has an atomic number of 20, but the given configuration is for the calcium atom before losing electrons. The number of electrons in the neutral atom is equal to the atomic number. The sum of electrons in the given configuration is \(2+2 + 6+2+6+2=18\) (but this is incorrect, actually \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}\) has \(2+2 + 6+2+6+2 = 20\) electrons, which is calcium (Ca)).
• Question 19: Gamma rays have the shortest wavelength and highest energy in the electromagnetic spectrum.
• Question 20: The valence shell is the outermost energy level of an atom.
• Question 21: A nonpolar covalent bond forms when the electronegativity difference (\(\Delta\)EN) is less than 0.5.
• Question 22: The noble gas core \([Ar]\) in \([Ar]4s^{2}3d^{10}4p^{2}\) is argon (Ar).
• Question 23: Aluminum (Al) has an atomic number of 13. Its electron configuration is \([Ne]3s^{2}3p^{1}\). To achieve a stable electron configuration (similar to neon), it loses three electrons, so its oxidation number is \(3+\).
• Question 24: Electronegativity increases across a period and decreases down a group. Oxygen (O) is in Group 16 and Period 2, sulfur (S) is in Group 16 and Period 3, helium (He) is a noble gas (has a stable electron configuration and does not tend to attract electrons in a bond in the same way as non - noble gases), and cesium (Cs) is in Group 1 and Period 6. So oxygen (O) has the greatest electronegativity among the given options.

Answer:

1. D. It loses one electron
2. A. Attract electrons in a chemical bond
3. A. Barium (Ba)
4. A. \(2+\)
5. D. Calcium (Ca)
6. A. Gamma rays
7. B. Outermost energy level
8. A. Less than 0.5 or very small
9. C. Argon (Ar)
10. A. \(3^{+}\)
11. A. Oxygen (O)