The principal quantum number n of Group 14 elements increases in the order C > Si > Ge > Sn > Pb. Which amongst these elements will have the least electron affinity ?
Question 2Select one:
a.
Sn
b.
Pb
c.
Ge
d.
C
a. Sn
To determine which element will have the least electron affinity among Group 14 elements, let's start by examining the trends in electron affinity across the group.
Electron affinity is the energy change that occurs when an atom gains an electron in the gaseous state. Generally, electron affinity tends to increase across a period from left to right and decrease down a group.
In Group 14, the elements are carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead (Pb).
Comparing these elements, we find that as the atomic number increases from C to Pb, the principal quantum number (n) also increases. The principal quantum number (n) is a measure of the size and energy level of an electron's orbital.
Since electron affinity tends to decrease down a group, we can conclude that the element with the largest value of the principal quantum number (n), which is Pb, will have the least electron affinity.
Therefore, b. Pb is the element that will have the least electron affinity among C, Si, Ge, Sn, and Pb.
To determine which element will have the least electron affinity amongst the Group 14 elements, we need to understand the relationship between the principal quantum number (n) and electron affinity.
The electron affinity is the energy released or absorbed when an atom gains an electron to form a negatively charged ion. It measures the attraction of an atom's nucleus for an additional electron.
In general, electron affinity tends to increase across a period (from left to right) on the periodic table. This is because, as you move across a period, the atomic radius decreases and the nuclear charge increases, leading to a stronger attraction for additional electrons.
However, electron affinity is also influenced by other factors, such as the electron configuration and stability of the atom. In the case of Group 14 elements, their electron affinities do not strictly follow the trend across a period due to these factors.
Now, let's analyze the given elements in Group 14:
C (Carbon) has an electron configuration of 1s² 2s² 2p².
Si (Silicon) has an electron configuration of 1s² 2s² 2p⁶ 3s² 3p².
Ge (Germanium) has an electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p².
Sn (Tin) has an electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p².
Pb (Lead) has an electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p².
Based on their electron configurations, we can observe that as we move down Group 14, the principal quantum number (n) increases, indicating that the valence electrons are further away from the nucleus.
In this case, the element with the least electron affinity would be Pb (Lead) because its valence electrons are the farthest from the nucleus compared to the other elements in the group.
Therefore, the answer to Question 2 is:
b. Pb (Lead)