To determine the correct order of the given elements from least electronegative to most electronegative, we need to understand the general trends in electronegativity on the periodic table.
Electronegativity tends to increase as you move from left to right across a period and decrease as you move down a group in the periodic table. This means elements on the far right (except for the noble gases) and toward the top of the periodic table are more electronegative than those on the left and toward the bottom.
Here are the elements from the given options:
- As (Arsenic)
- Br (Bromine)
- Ca (Calcium)
- Sr (Strontium)
First, we identify the positions of these elements on the periodic table:
- Calcium (Ca) is in Group 2, Period 4.
- Strontium (Sr) is in Group 2, Period 5.
- Arsenic (As) is in Group 15, Period 4.
- Bromine (Br) is in Group 17, Period 4.
To arrange these elements in order of increasing electronegativity, we consider their trends:
1. Group 2 Elements:
- Calcium (Ca): Since it is higher up in the group, it is slightly more electronegative than Strontium (Sr).
2. Arsenic (As) and Bromine (Br):
- Both are in the same period (Period 4), but Bromine is in Group 17 while Arsenic is in Group 15. Thus, Bromine is more electronegative than Arsenic due to being more to the right on the periodic table.
Thus, we can deduce the order from least to most electronegative:
- Calcium (Ca) → Strontium (Sr) → Arsenic (As) → Bromine (Br)
Hence, the correct order from the given choices is:
- Ca, Sr, As, Br
So the correct choice is:
(3) Ca, Sr, As, Br
This is the correctly ordered group of elements from least electronegative to most electronegative.
