Ions: isoelectronic Noble Gas

Question

A monatomic ion with a charge of +1 has an electronic configuration of 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶.

This ion is a(n) _______cationanion.

What is the chemical symbol of the noble gas this ion is isoelectronic with? 

What is the formula of the ion? 

Answer 1

Add up all of the electrons. There are 54 of them in your configuration. Then look on your periodic table to find the element whose atomic number is 54. You should find the element Xenon (Xe). Since your ion has a +1 charge, it must have lost one electron. Therefore the original element will have an atomic number of 54+1=55. This is the element Cesium (Cs). The Cesium Ion will have the formula Cs+

Since it is a positive ion, it is a cation. One way to remember the difference between cation and anion is to thinks of cats. Cats make you happy and so are Positive like the CATion. Also, anion sounds like onion which can make you cry when cutting them, so an anion is negative.