Chapter 8 - Chapter 8 In nature, nonmetals elements are...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 8 In nature, nonmetals elements are made up of molecules and in solid metallic elements, each atom is surrounded by 8 to 12 neighbors. Atoms “stick” to one another through interactions between valence electrons. Ionic compounds consist of transfer from the valence electrons of a metal atom to the valence shell of a nonmetallic atom which hold the ions into a crystal lattice. Ionic compounds are capable of conducting electricity when melted due to the moving charges. Molecular compounds are held together by sharing valence electrons. The attraction of the positively charged nuclei for electrons between them pulls the nuclei together. 8.1 G.N.Lewis suggested that when atoms join together chemically, they have electron configurations of the noble gases (they are stable). Covalent Bonds – Valence electrons are shared between atoms, connecting them into molecular compounds. How does this occur? If two atoms of hydrogen are brought close together so the 1s levels overlap, the electrons are attracted by each nucleus. 8.2 When a covalent bond is formed, the valence electrons are in the same shell. The number of covalent bonds an atom can form is determined by the number of electrons that the atom must share to achieve a noble gas configuration. Single covalent bond – Two atoms share one pair of electrons. Lewis structure – A molecule shows all valence electrons as dots of lines that represent covalent bonds. Octet Rule: To form bonds, main group elements gain, lose, or share electrons to achieve a stable electron configuration characterized by eight valence electrons. The difference between the lone pair electrons and bonding electrons is the lone pair are the pairs that are not bonded and the ones that are shared are the bonded. Steps for Writing Lewis Structures 1. Count the total number of valence electrons in the molecule or ion. 2. Use atomic symbols to draw a skeleton structure by joining the atoms with shared pairs of electrons (a single line) – The skeleton structure indicates the attachment of terminal atoms to a central atom, which is usually the first one written in the formula. 3. Place lone pairs of electrons around each atom (except H) to satisfy the octet rule, starting with the terminal atoms
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4. Place any leftover electrons on the central atom, even if it will give the central atom more than an octet. 5. If the number of electrons around the central atom is less than eight, change single bonds to the central atom to multiple bonds – If multiple bonds are needed, the terminal atom’s lone pair electrons are bonded with the central atom’s electrons to form double or triple bonds. Although Lewis dot diagrams are useful, they do not account for many things like the fact that the bonded electrons exist in between the nuclei and the diagram does not show the shape of the molecule. 8.3
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 6

Chapter 8 - Chapter 8 In nature, nonmetals elements are...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online