a potassium atom:an aluminum ion:a bromine atom:a selenium atom
The plastic bottle's n't closed.
Potassium loses electrons [it's a metal] Aluminum loses electrons too [it's also a metal] Bromine gains electrons [it's not a metal] Selenium gains electrons [it's a non-metal too]Selenium 2,8,18, 6 [therefore it gains 4] and becomes negative Potassium 2,8,8, 1 [loses one] so therefore becomes positive Aluminum 2,8,3 [gives away three] so it becomes positive Bromine 2,8, 18, 7 [gains three] so it becomes negative Non-metals become negative when they form ions and metals become positive when they form ions.
