According to the duplet rule, a maximum of 2 electrons makes the K shell stable. Why does calcium, which has 2 electrons, react by losing 2 electrons?
Answer (3)
cmiiw ;
The question you're asking is related to basic chemistry, specifically the behavior of elements in terms of their electron configurations and how they achieve stability.
According to the duplet rule, an atom is stable when it has 2 electrons in its first shell, known as the K shell. This rule, however, mainly applies to very light elements, such as hydrogen and helium, which have only one energy level that can hold up to 2 electrons.
Calcium is an element found in the fourth period of the periodic table, and it is known for having a more complex electron configuration. Calcium has an atomic number of 20, which means it has 20 electrons. The electronic configuration of calcium is:
1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 4 s 2
Here is how this configuration is arranged:
K shell (1s) : has 2 electrons - completely filled and stable.
L shell (2s and 2p) : has 8 electrons - completely filled and stable.
M shell (3s and 3p) : has 8 electrons - completely filled and stable.
N shell (4s) : has 2 electrons.
Even though the K shell is stable with its 2 electrons, calcium has electrons in higher energy levels (or shells). Elements seek to be stable by achieving a full valence shell, resembling the nearest noble gas configuration.
Calcium has 2 electrons in its outermost shell (4s), and it can lose these 2 electrons to achieve a noble gas configuration similar to argon ( 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 ), which is a more stable, lower energy state called the octet configuration (8 electrons in its outermost shell). By losing its 4s electrons, calcium achieves this stability.
This property makes calcium a reactive metal, as it tends to lose these 2 electrons to form a C a 2 + ion, aligning itself with the stability of the noble gas continuation in the octet rule, rather than the duplet rule applicable for very light atoms.
Calcium, which has 2 electrons in its outermost shell (4s), loses these electrons to achieve a more stable configuration similar to argon, which has 8 electrons in its outermost shell. This behavior is influenced by the octet rule, not just the duplet rule that applies to light elements. Therefore, while the K shell is stable, calcium seeks greater stability by forming a C a 2 + ion.
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