Chemical bonds Section 4 Reinforcement

Protons, Neutrons, Electrons, and Where to Find Them An element can have from one to eight electrons in its OUTERenergy level.An atom's NUCLEUScontains its protons and neutrons.An atom's electrons are most likely to be found in the ELECTRON CLOUD.The first energy level of an atom can hold only TWOelectrons.The second energy level of atom can hold EIGHTelectrons. Alkali Metals Halogens Elements in Group 1, like Sodium, become more stable by LOSING their outer level electron. These elements form POSITIVELYcharged IONS, because they have more protons than electrons.Elements in Group 17, like Chlorine, become more stable by GAININGan electron and forming a NEGATIVELY charged ion, because they have more electrons than protons. The attraction between sodium ions and chlorine ions form an IONICbond. Covalent Bonds Unlike sodium and chlorine, some atoms become more stable by SHARINGelectrons and forming COVALENTbonds instead of forming charged ions.The bonds in a molecule made of two nitrogen atoms are covalent NONPOLARbonds, because both atoms share the electrons EQUALLY.The bonds in a molecule of water are covalent POLARbonds, because oxygen DOESN'Tshare the electrons with hydrogen equally. Formula Components 2 Atoms of Sodium & 1 Atom of Sulfur 2 Atoms Hydrogen, 1 Atom of Carbon, 3 Atoms of Oxygen 1 Atom of Silicon 2 Atoms of Oxygen 1 Atom Potassium 1 Atom Iodine