1. mass number,morns of the same clement with difierent numbers of neutrons 2. chemical symbol 3, isotopes

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1 Name: Date: Period: Chemistry Review The basic unit of matter is the atom. The atom is made up of even smaller particles. Three of these subatomic particles are the proton, the neutron, and the elcetron. Both the positively charged protons and the electrically neutral neutrons form the nucleus of the atom. The negatively charged electrons travel around the nucleus of the atom in a series of distinct energy levels. The number of protons in the nucleus of an atom, or the atomic number, Is used to Identify the atom. The total number of protons and neutrons in the nucleus is calla the mass number. Substances that consist entriely of one type of atom are called elements. Each element Is represented by a chemical symbol. The number of protons in an atom of an element never changes. The number of neutrons however, may vary from one atom of an element to the next. Atoms of the same element that have different numbers of neutrons are called isotopes. Certain kinds of isotopes are radioactive. Substances that consist of more than one type of atom are called chemical compounds. Most of the materials in the living world are compounds. Match the numbered terms with their definitions. Write the letter of the definition that corresponds with each term In the space provided mass number,morns of the same clement with difierent numbers of neutrons 2. chemical symbol 3, isotopes atomic number substance that contains two or more difierent kinds of atoms..... S. nucleus /climber of protons in an atom 6. neutron,..frartorthand way of representing an element 7. element Ate-Center of the atom _,f posftivelychargad particle nr subatomic particle located outside the nucleus of the atom 8. proton Ai/electrically neutral subatomic particle.. O. chemical compound.umber of protons plus the number of neutrons in an atom C10. electron J.--substance consisting of only one type of atom 11. In the space below, draw and label the following parts of an atom: electron, neutron, proton, nucleus and energy level.

2 Counting Atoms The formula for a compound indicates the elements that make up the compound and the number of atoms of each element present in the compound. These numbers of atoms are indicated by the use of small numbers called subscripts. Sometimes groups of atoms act as a single atom. Such a group of atoms is called a radical. if a radical Is used In a formula more than once, the radical is put in parentheses and the subscdpt appears outside the parentheses. When a subscript appears outside the parentheses, It indicates that all the demerits inside parentheses should be multiplied by that StIbratiptFOr example, the formula Fe(010 3 indicates the combination of one atom of iron, Fe, three atoms of oxygen, 0, and three atoms of hydrogen, H. In the following examples, list each element In the compound and the number of atoms of each element present. The first example has been done for you. You may already be familiar with some of the compounds. Name list Formula Atoms In Formula Calcium carbonate Limestone CaCO1 Ca = calcium 1 Aspirin Pain reliever C Magnesium hydroxide Found In milk of' magnesia Paradichlorobenzene Moth crystals Trinitrotomene CST) Explosive C e_. tii I Atoms that have the same number of protons and electrons are elect ically neutral. However, atoms may gain or lose electrons during chemical reactions. This creates an imbalance of negative and positive charges. Atoms may have a negative charge because they have gained extra electrons. Such atoms are called negative ions. Other atoms may have a positive charge because they have lost electrons. These atoms are called positive ions. The following table contains information about several atoms. Using what you have learned In the preceding paragraph, complete the table. Enough information has bean provided for you to fill In all the blanks. Atomic # = # of protons Mass ft = it of protons + # of neat ons eiemem Atomic Number Mass Number Aluminum (AI) Bromine (Bd Calton (0) 8 SC Protons (2) Number ot Neutrons l tic Elections is li. 6 ti Carbon (t) 6 i4.0 a Helium (He) 2 4 Isotope, fort, or Neutral Mont { neutral atom

3 The following diagram shows a small portion of the periodic table of the elements. Use the information in the diagram to answer questions 1 through 9. He 12 Na Mg :mob mapnoeboni 4 ibeon Carbon wathg a 0 Mos Fluorine t3 Ne a is AU Si iy1155 CI Ar Alurninuirr, Wren ap nhotphnms Srhi at Chlorine 35 ATM oo 1. What is the boldfaced letter or letters in the center of the box? tik\l- 2. What is the number above the boldfaced letter or letters? '&$ AVa 3. Whthir it. the nuber below the name of the element? 4-( - 'r$`-l '? lj Use the periodic table above to till out the following table. Verner?: Carbon incises In Atom 4.. Li ' Neutrons In Atom Number ol in Atom in First e Number ol in Second in Third aicrine Heiman..,. liydir og en 1.ilhiu m t.., ) - ) /..- C -1.. Chemical Bonding Use the following terms to label the structures shown in the diagram below: electron, nucleus, neutral atom, positive ion, negative ion, ionic bond. Af p Chlorin (CU (*mote aloe,

4 1. What basic process is shown in the previous diagram? 2. How many electrons can the innermost energy level hold? The outermost? 3. What kind of bond is shown? Explain. c 4. How does an ion differ from a neu ral atom? Use the following terms to label the structures shown in the diagram below: electron, shared electron, molecule. 1 fl 9 dr a 9 a 0 r d, Oxy 'en (Oa) v i,stat0-5. What kind of bond is shown in the diagram? Explain. 6. What do the dots in the above diagram represent? e 7. What is the above diagram called? C) Chemical Reactions ) `- Any process in which a chemical change occurs is known as a chemical reaction. As you learned in this section, a chemical reaction converts elements or compounds known as reactatnts into elements or compounds known as products. A chemical equation uses symbols'and formulas to descrive a chemical reaction. In the chemical reactions described below, identify the reactant(s) and the product(s). Then ' write a balanced equation for each reaction. el -N-Y` 1. A sodium ion (Na) eacts with a chlorine ion (CO to form the compound sodium chloride (NaCI). Reactant(s): b,c)("*"" C, Product(s): ic-50- Equation: IC* 13? aik 7 \-)c- e-1 2. Magnesium oxide (MgO) is produced when a magnesium ion (Mg &) reacts with an oxygen ion (02). it+ Reactant(s): Ner 4- Product(s): Equation: t s..1v. C

5 BALANCING EQUATIONS Name Balance the following chemical equations. 2. jkl 2 + > 2_ N > 3NH3 4. CH 4 +2_02-4 CO2 +2H KI jkci --> ,, S _ ,..H202 H 2O + 0, Na > -2,NaOH + 9,-2,H > 2, KCIO 3 ---> -7 KCI K3PO 4 HCI ---> 3 KCI + H3PO4 A2. CO 2 + H2O H K20 + H 2O _KOH 14. Mg +7 HCI MgCl2 + H2 19 KOH + H2SO4 K2SO4 H2O Biology IF Instructional Fair, Inc