Question

use the trends notes in the next page to answer the following questions: 1. rank the following elements by increasing atomic radius: carbon, aluminum, oxygen, potassium. 2. rank the following elements by increasing electronegativity: sulfur, oxygen, neon, aluminum. 3. why does fluorine have a higher ionization energy than iodine? 4. why do elements in the same family generally have similar properties? 5. indicate whether the following properties increase or decrease from left to right across the periodic table. a. atomic radius (excluding noble gases) b. first ionization energy c. electronegativity 6. what trend in atomic radius occurs down a group on the periodic table? what causes this trend? 7. what trend in ionization energy occurs across a period on the periodic table? what causes this trend? 8. circle the atom in each pair that has the largest atomic radius. a al or b b. na or al c. s or o d. o or f e. br or cl f. mg or ca

Explanation:

Step1: Recall atomic - radius trend

Atomic radius increases down a group and decreases across a period. Carbon (C) is in period 2, oxygen (O) is in period 2 (but to the right of C), aluminum (Al) is in period 3, and potassium (K) is in period 4. So the order of increasing atomic radius is oxygen < carbon < aluminum < potassium.

Step2: Recall electronegativity trend

Electronegativity increases across a period and decreases down a group. Neon (Ne) is a noble - gas and has very low electronegativity. Aluminum (Al) is a metal with low electronegativity. Sulfur (S) and oxygen (O) are non - metals, with oxygen more electronegative than sulfur. So the order of increasing electronegativity is aluminum < neon < sulfur < oxygen.

Step3: Explain ionization energy difference

Fluorine (F) is in period 2 and iodine (I) is in period 5. Fluorine has a smaller atomic radius and a higher effective nuclear charge. The outermost electrons in fluorine are closer to the nucleus and more strongly attracted, so it requires more energy to remove an electron, resulting in a higher ionization energy.

Step4: Explain similar properties in a family

Elements in the same family have the same number of valence electrons. Valence electrons determine the chemical properties of an element, so elements in the same family generally have similar chemical properties.

Step5: Identify periodic trends

a. Atomic radius (excluding noble gases) decreases from left to right across the periodic table because the effective nuclear charge increases while the number of electron shells remains the same.
b. First ionization energy increases from left to right across the periodic table as the effective nuclear charge increases and it becomes more difficult to remove an electron.
c. Electronegativity increases from left to right across the periodic table as the ability of an atom to attract electrons in a chemical bond increases with increasing effective nuclear charge.

Step6: Atomic radius trend down a group

Atomic radius increases down a group. This is because as you go down a group, the number of electron shells increases, and the outermost electrons are further from the nucleus.

Step7: Ionization energy trend across a period

Ionization energy increases across a period. The effective nuclear charge increases, making it harder to remove an electron.

Step8: Compare atomic radii in pairs

a. Al has a larger atomic radius than B because Al is in a lower period.
b. Na has a larger atomic radius than Al because Na is to the left of Al in the same period.
c. S has a larger atomic radius than O because S is in a lower period.
d. O has a larger atomic radius than F because O is to the left of F in the same period.
e. Br has a larger atomic radius than Cl because Br is in a lower period.
f. Ca has a larger atomic radius than Mg because Ca is in a lower period.

Answer:

1. oxygen < carbon < aluminum < potassium
2. aluminum < neon < sulfur < oxygen
3. Fluorine has a smaller atomic radius and higher effective nuclear charge, so its outermost electrons are more strongly attracted to the nucleus, requiring more energy to remove an electron.
4. Elements in the same family have the same number of valence electrons, which determine chemical properties.
5. a. Decrease; b. Increase; c. Increase
6. Atomic radius increases down a group. The number of electron shells increases.
7. Ionization energy increases across a period. The effective nuclear charge increases.
8. a. Al; b. Na; c. S; d. O; e. Br; f. Ca