Table of Contents Chapter Preview 5.1 Atoms, Bonding, and the Periodic Table 5.2 Ionic Bonds 5.3 Covalent Bonds 5.4 Bonding in Metals

Section 1: Atoms, Bonding, and the Periodic Table How is the reactivity of elements related to valence electrons in atoms?

Section 1: Atoms, Bonding, and the Periodic Table How is the reactivity of elements related to valence electrons in atoms? The number of valence electrons in an atom of an element determines many properties of that element, including the ways in which the atom can bond with other atoms.

Valence Electrons and Bonding The number of valence electrons in an atom of an element determines many properties of that element, including the ways in which the atom can bond with other atoms.

Section 1: Atoms, Bonding, and the Periodic Table What does the periodic table tell you about the atoms of elements?

Section 1: Atoms, Bonding, and the Periodic Table What does the periodic table tell you about the atoms of elements? The periodic table reveals the underlying atomic structure of atoms, including the arrangement of the electrons.

How the Periodic Table Works The periodic table reveals the underlying atomic structure of atoms, including the arrangement of the electrons.

Electron Dot Diagram An electron dot diagram includes the symbol for the element surrounded by dot. Each dot stands for one valence electron.

Step 1: Write the symbol of the atom you are drawing the electron dot diagram for in the middle of your paper. This symbol represents the nucleus of the atom and each of the four sides represents an orbital. Step 2: Locate the element you are drawing an electron dot diagram for on the periodic table of elements. Find the number of electrons in one atom of the element. The number of electrons is the same as the element's atomic number. Step 3: Find the number of valence electrons by subtracting the number of electrons in each level from the total number of electrons. There are two electrons in the first level and eight in the second, third and fourth levels. The diagram will represent only the outermost level of the electron field. Take the number of electrons and subtract the number of electrons in each level until you come to a level that is not entirely full. For the noble gases, the last level will be full, with no electrons left over, and this is the level you will draw. Step 4: Place the first two dots on the right side of the element symbol. This side is referred to as the “s” orbital. Step 5: Place the remaining dots in a counterclockwise fashion around the symbol.

The Periodic Table As the atomic number increases, the number of electrons also increases. As a result, the properties of the elements change in a regular way across a period.

End of Section: Atoms, Bonding, and the Periodic Table

Citations http://upload.wikimedia.org/wikipedia/commons/thumb/a/a9/Atom.svg/198px-Atom.svg.png http://schoolhouse1.fenn.org/dduane/Science8th/bib_at1.jpg https://vinstan.wikispaces.com/file/view/P.gif http://images.google.com/imgres?imgurl=http://cdn-write.demandstudios.com/upload//8000/900/50/2/48952.jpg&imgrefurl=http://www.ehow.com/how-does_4568765_electron-dot-diagram-work.html&usg=__mAeFs3IxkoVZDs188225ZlWtgeY=&h=1536&w=2048&sz=291&hl=en&start=1&tbnid=PsP5jmiNNZGbUM:&tbnh=113&tbnw=150&prev=/images%3Fq%3Dhow%2Bto%2Belectron%2Bdot%2Bdiagram%26gbv%3D2%26hl%3Den%26sa%3DG

Section 2: Ionic Bonds How do ions form bonds? 13

Section 2: Ionic Bonds How do ions form bonds? Ionic bonds form as a result of the attraction between positive and negative ions. 14

Ions and Ionic Bonds You and a friend walk past a market that sells apples for 40 cents each and pears for 50 cents each. You have 45 cents and want an apple. Your friend also has 45 cents but wants a pear. 15

What is an ion? When an atom gains or loses one or more electrons, the charged particle that results is called an ion. A known fact is that oppositely charged particles are attracted to each other. This strong force of attraction is what keeps the atoms stuck together as a compound.

Ions and Ionic Bonds When an atom loses one of its electrons, it becomes a positively charged ion. The atom that gains the electron becomes a negatively charged ion. 17

Ions and Ionic Bonds Ions are atoms or groups of atoms that have lost or gained electrons. Polyatomic ions is a group of atoms that reacts as a unit. 18

Section 2: Ionic Bonds How are the formulas and names of ionic compounds written? 19

Section 2: Ionic Bonds How are the formulas and names of ionic compounds written? When ionic compounds form, the ions come together in a a way that balances out the charges on the ions. Subscripts tells you the ratio of elements in the compound. For an ionic compound, the name of the positive ion comes first, followed by the name of the negative ion. 20

Ions and Ionic Bonds Ionic bonds form as a result of the attraction between positive and negative ions. 21

Section 2: Ionic Bonds What are the properties of ionic compounds? 22

Properties of Ionic Compounds Hard brittle solids high melting points When dissolved in water, they conduct electric current. 23

Polyatomic Ions Polyatomic Ions: - ions that are made of more than one atom and reacts as a unit, having a positive or negative charge. Also known as “radicals”. 24