an atom of element x has one more shell of electrons than an atom of beryllium, but it has one less valence…

an atom of element x has one more shell of electrons than an atom of beryllium, but it has one less valence electron than beryllium. which element is element x?\n- sodium (na)\n- boron (b)\n- magnesium (mg)\n- lithium (li)
Answer
Explanation:
Step1: Determine beryllium's electron - shell and valence - electron info
Beryllium (Be) has atomic number 4. Its electron configuration is 1s²2s². It has 2 electron - shells and 2 valence electrons.
Step2: Determine element X's electron - shell and valence - electron info
Element X has one more shell of electrons than beryllium, so it has 3 electron - shells. It has one less valence electron than beryllium, so it has 1 valence electron.
Step3: Identify the element
The element with 3 electron - shells and 1 valence electron is sodium (Na). Its electron configuration is 1s²2s²2p⁶3s¹.
Answer:
sodium (Na)