Question

determine if the listed pairs of elements have similar or different properties.
7
potassium & rubidium
calcium & barium
a
b
sodium & chlorine
helium & krypton
c
d
phosphorus & oxygen
lithium & fluorine
e
f
which element has the largest electronegativity?
8
which group (name) would have the lowest ionization energies?
9
which group (name) has the highest ionization energies?
10

Explanation:

• Question 7: Elements in the same group have similar properties.
• a. Potassium (K) is in Group 1, Rubidium (Rb) is in Group 1. They are both alkali metals and have similar properties (e.g., highly reactive, form + 1 ions).
• b. Calcium (Ca) is in Group 2, Barium (Ba) is in Group 2. They are alkaline - earth metals and have similar properties (e.g., form + 2 ions, reactive).
• c. Sodium (Na) is in Group 1, Chlorine (Cl) is in Group 17. They have different properties (Na is a metal, Cl is a non - metal).
• d. Helium (He) is in Group 18 (noble gas), Krypton (Kr) is in Group 18. They have similar properties (unreactive, full valence shells).
• e. Phosphorus (P) is in Group 15, Oxygen (O) is in Group 16. They have different properties.
• f. Lithium (Li) is in Group 1, Fluorine (F) is in Group 17. They have different properties.
• Question 8: The element with the largest electronegativity is generally in the upper - right of the periodic table (excluding noble gases). But if we consider the options, we need to recall the trends. However, if we assume the options are from the given pairs (though the question is a bit unclear in formatting), but if we consider general trends, noble gases have very low electronegativity (close to 0 as they don't tend to gain electrons easily). But if we assume the intended answer is based on the fact that metals have lower electronegativity than non - metals. If we consider the pairs in question 7 (maybe a formatting error), but if we assume the element with the lowest electronegativity (since the question is "has the largest electronegativity" but maybe a mis - label, if it's "has the lowest", alkali metals have low electronegativity. But if we consider the correct trend, fluorine has the highest electronegativity among common elements. But since the options are not clear, if we assume from the pairs in question 7 (again, formatting issue), but noble gases (He, Kr) have very low electronegativity.
• Question 9: Ionization energy is the energy required to remove an electron. Noble gases have very high ionization energies (stable electron configurations). Group 1 (alkali metals) have low ionization energies. Group 18 (noble gases) have the highest ionization energies among the main groups.
• Question 10: Group 18 (noble gases) have the highest ionization energies due to their stable full - valence - shell electron configurations.

Answer:

1. a. Potassium & Rubidium, b. Calcium & Barium, d. Helium & Krypton have similar properties; c. Sodium & Chlorine, e. Phosphorus & Oxygen, f. Lithium & Fluorine have different properties.
2. (Assuming correct element, if based on general trend, Fluorine has high electronegativity, but with the given pairs in 7, noble gases (He, Kr) have low electronegativity. If the question is mis - labeled and should be “lowest”, alkali metals (e.g., from pair a in 7 - K, Rb) have low electronegativity).
3. Group 1 (alkali metals) have low ionization energies.
4. Group 18 (noble gases) have the highest ionization energies.