180 likes | 330 Views
CHEMICAL BONDS. CHAPTER 2. Definition- the attractive force that holds two or more atoms or ions together. COMPOUND. Defined as atoms of 2 or more elements that combine together chemically to form a new substance with different chemical properties
E N D
CHEMICAL BONDS CHAPTER 2 Definition- the attractive force that holds two or more atoms or ions together
COMPOUND Defined as atoms of 2 or more elements that combine together chemically to form a new substance with different chemical properties Example hydrogen gas + oxygen gas = WATER Give me 3 examples of compounds.- Brainstorm
MOLECULE 2 or more atoms forming a chemical bond, smallest unit of a compound that retains the properties of that compound Example : H2 O Two hydrogen atoms chemically bonded to one oxygen atom
Why are Compounds Made? Compounds are formed to make the atoms more stable. An atom is chemically stable WHEN ITS OUTERMOST ENERGY LEVEL IS FULL OF ELECTRONS
3 types of bonds • METALLIC BOND- bond between two metals - • COVALENT BOND- bond between two non metals • IONIC BOND – bond between a METAL and NONMETAL
IONIC BONDbond formed between two ions by the transfer of electrons
IONIC BOND IONIC BOND- the attraction of positive and negative electrical charges of the ions to each other. Step 1- Valence electrons are lost or gained and the atom becomes an ion Step 2- Ionic charges are attracted to each other Ionic bonds are WEAK BONDS and easily broken in water and allow the water to conduct electricity
How can items with the same charge make a molecule? ANSWER- The SHARE the valence electrons Example O2 and CO2
COVALENT BONDS Two or more atoms share one or more pairs of electrons. Covalent bonds are much stronger than ionic bonds. IN your notes DRAW THE COVALENT BONDS of 2 hydrogen atoms and 1 oxygen atom to make a water molecule.
COVALENT BONDS • In science we typically draw the covalent bonds by drawing a line between the two elements • One line- means the sharing of 2 electrons (1 pair) • Two lines- means the sharing of 4 electrons (2 pair) • Three lines- means the sharing of 6 electrons (3 pair) • Draw the symbol of a water molecule showing the covalent bonds
Metallic Bond • Formed between atoms of metallic elements • Electron cloud around atoms • This is sometimes described as "an array of positive ions in a sea of electrons". • Good conductors at all states, lustrous, very high melting points • Examples; Na, Fe, Al, Au, Co