Middle School Science Science STAAR Need to Know STAAR Need to Know 1

Claim: 2 Metalloids (have some properties of metals and some properties of non metals)

1.Malleable (broken 1. not malleable into thin plates) (brittle, break easily) 2. Ductile (made into 2. not ductile thin wires) 3. Good conductors 3. poor conductors of of heat and electricity heat and electricity 4. metallic shine 4. no (rarely) metallic or luster shine or luster 5. Easily looses 5. easily gains electrons electrons

4 PCES The element sulfur has an atomic number of 16, and an atomic mass of 32. It is on the right of the zig-zag on the periodic table. Based on this information, to which class of elements does sulfur most likely belong? A. metals B. metalloids C. nonmetals D. solids

Problem: Is sulfur a metal, non metal, or metalloid? 5

Claim: 7 metalloids

Scientific Explanation: Sulfur is a non metal based on location and properties. 8

Metals Metalloids Non metals Group 18 is called Noble Gas. They do not react with other elements

1.Malleable (broken 1. not malleable into thin plates) (brittle, break easily) 2. Ductile (made into 2. not ductile thin wires) 3. Good conductors 3. poor conductors of of heat and electricity heat and electricity 4. metallic shine 4. no (rarely) metallic or luster shine or luster 5. Easily looses 5. easily gains electrons electrons

11 PCES How many atoms are represented in the formula CaCO 3 ? A. three B. four C. five D. six

Problem: How many atoms are represented in the formula CaCO 3 ? 12

Claim: 13

14 Scientific Explanation: atoms in CaCO 3 Ca = 1 C = 1 O 3 = 3 Total = 5

15 Journal Entry – Case One Calculate the number of oxygen atoms of the molecule represented in the following formula: 4Al 2 (SO 4 ) 3 Record your answer and fill in the bubbles on your answer document. Be sure to use the correct place value.

16 Problem: Calculate the number of oxygen atoms of the molecule represented in the following formula: 4Al 2 (SO 4 ) 3

17 4Al 2 (SO 4 ) 3

18 Claim:

19 Scientific Explanation: Oxygen atoms in 4Al 2 (SO 4 ) 3 = coefficient x subscript = coefficient x (bracketed subscript x subscript) = 4 x ( 3 x 4) = 4 x 12 = 48

20 Case Two REACTANTS PRODUCTS _____Al + ____ CuSO 4 _____Al(SO 4 ) 3 + _____Cu The equation above is an unbalanced equation. Find the coefficients that will balance the following reaction. Record your answer and fill in the bubbles on your answer document. Be sure to use the correct place value.

21 Problem: Find the coefficients that will balance the reaction.

22 Scientific Explanation: Formula number = coefficient x subscript of atoms

23 Reactants Al + 3CuSO 4 Al = 1 atoms Cu = 3 atoms S = 3 atoms O = 12 atoms

24 Products 1Al(SO 4 ) 3 + 3Cu Al = 1 atoms Cu = 3 atoms S = 3 atoms O = 12 atoms

25 REACTANTS PRODUCTS 1Al + 3CuSO 4 1(SO 4 ) 3 + 3Cu Al + 3CuSO 4 (SO 4 ) 3 + 3Cu

subatomic charge location particles _______________________________________ proton + inside nucleus _______________________________________ neutron no charge inside nucleus (neutral) _______________________________________ electron - in electron cloud _______________________________________

Atoms are building blocks of elements Atoms in each unique element are the same. (Ex: Every oxygen element has the same # of protons) Atoms are different from atoms of other elements (Ex: Hydrogen has a different # of protons than oxygen) Two or more different atoms bond in simple ratios to form compounds (Ex: Hydrogen & oxygen can chemically combine to form water- H 2 O ) STAAR Need to Know27

Metals Metalloids Nonmetals Group 18 is called Noble Gas. They do not react with other elements

1.Malleable (broken 1. not malleable into thin plates) (brittle, break easily) 2. Ductile (made into 2. not ductile thin wires) 3. Good conductors 3. poor conductors of of heat and electricity heat and electricity 4. metallic shine 4. no (rarely) metallic or luster shine or luster 5. Easily looses 5. easily gains electrons electrons

.. shiny- high luster good conductor of heat

.. Good conductor of electricity malleable – beaten into thin plates Ductile – drawn into thin wires

Brittle – break easily no luster not good conductors of heat

STAAR Need to Know33

Who am I?

1.I am positively charged particle of an atom.

proton

2.I am negatively charged particle of an atom.

electron

3.I am neutrally charged particle of an atom.

neutron

4. We are found in the nucleus of an atom.

proton and neutron

We are the three subatomic particles of an atom.

proton, neutron, and electron

An atom has no charge because………

……number of protons is equal to number of electrons.

Problem Solving

1. An atom of a certain element has atomic number 5. What is its number of protons, electrons and neutrons?

atomic no. = protons = electrons A = P = E 5 = 5 = 5

mass no. m 11 - atomic no. - a - 5 neutrons n 6

2. An atom of a certain element has mass number 84. What is its number of protons, electrons and neutrons?

atomic no. = protons = electrons A = P = E 36 = 36 = 36

mass no. m 84 - atomic no. - a -36 neutrons n 48

3. An atom of a certain element has 16 protons. What is its mass number and number of neutrons?

atomic no. = protons = electrons A = P = E 16=16=16

mass no. m 32 - atomic no. - a -16 neutrons n 16

4. An atom of a certain element has atomic number 20. What is its number of protons, electrons and neutrons?

atomic no. = protons = electrons A = P = E 20 = 20 = 20

mass no. m 40 - atomic no. - a -20 neutrons n 20

5. An atom of a certain element has 11 protons. What is its atomic number and number of neutrons?

atomic no. = protons = electrons A = P = E 11=11=11

mass no. m 23 - atomic no. - a -11 neutrons n 12

6. An atom of a certain element has 17 protons. What is its mass number and number of neutrons?

atomic no. = protons = electrons A = P = E 17=17=17

mass no. m 35 - atomic no. - a -17 neutrons n 18

7. An atom of a certain element has 18 protons. What is its mass number and number of neutrons?

atomic no. = protons = electrons A = P = E 18=18=18

mass no. m 40 - atomic no. - a -18 neutrons n 22

1. Mercury is an element. Which of the following would be the same for all atoms of mercury? A.the total number of protons and neutrons B.the number of protons C.the number of electrons D.the number of neutrons

B

2.How are elements arranged in the periodic table? A.by atomic mass B.by atomic number C.Alphabetically D.by the date of discovery

B

3.Atoms that have the same number of valence electrons A.belong to the same family/group of elements. B.must be atoms of the same element C.are all metallic elements. D.are all nonmetallic elements.

A

4. Most of the _________ of an atom is concentrated in the nucleus. A. space. B. mass C.are all metallic elements. D.are all nonmetallic elements.

B

5. The outer ______ are the parts of an atom that are involved in chemical reactions. A. protons B. electrons C. protons and neutrons D. electrons and protons

B

6. Which of the following statements is true? A.The nucleus of an atom contains protons and neutrons. B.Individual atoms can be seen with the naked eye. C.Electrons do not have mass. D.Protons are located outside the nucleus of an atom.

A

7. The part of an atom that would be found outside the nucleus is the _______. A. neutron B. positron C. proton D. electron

D

8.Which piece of information would best helps us identify an element? The number of…….. A. neutrons the element has B. charge the element has C.protons the element has D. electrons the element has

C

9. Where in an atom are neutrons located? A.in areas of probability B.in the photons C.in the nucleus D.in orbitals

C

10. An uncharged atom has six electrons. The nucleus of this atom must contain __ protons. A. Five B. Eight C. Seven D. Six

D

Counting atoms

1H2O11H2O1 O HH or 1 molecule of water = two hydrogen atoms and one oxygen atom

C 6 H O 2 6CO 2 + 6H 2 O + energy C 6 H 12 O 6 C = __ atoms H = __ atoms O = __ atoms and 6O 2 O = __ atoms Total reactant atoms = ______.

C 6 H O 2 6CO 2 + 6H 2 O + energy.

1. C 6 H O 2 6CO 2 + 6H 2 O + energy C 6 H 12 O 6 + 6O 2 C = __ atoms H = __ atoms O = __ atoms.

C 6 H O 2 6CO 2 + 6H 2 O + energy C 6 H 12 O 6 + 6O 2 C = 6 atoms H = 12 atoms O = 18 atoms.

Total reactant atoms = ____________

Total reactant atoms = 36

2. C 6 H O 2 6CO 2 + 6H 2 O + energy 6CO 2 + 6H 2 O C = atoms H = __ atoms O = __ atoms.

C 6 H O 2 6CO 2 + 6H 2 O + energy 6CO 2 + 6H 2 O C = 6 atoms H = 12 atoms O = 18 atoms.

Total product atoms = ____________

Total product atoms = 36

C 6 H O 2 6CO 2 + 6H 2 O + energy C 6 H 12 O 6 C = 6 atoms H = 12 atoms O = 6 atoms and 6O 2 O = 12 atoms Total reactant atoms = 36.

C 6 H O 2 6CO 2 + 6H 2 O + energy.

3. How many atoms of carbon are formed in the products? The formula is 6CO 2 no. of atoms = coefficient x subscript no. of C atoms = ____

3. How many atoms of carbon are formed in the products? The formula is 6CO 2 no. of atoms = coefficient x subscript no. of C atoms = 6 x 1 = 6

continued…………

1.Number of Na atoms in 3NaCl = ___

Na atoms in 3NaCl no. of Na atoms = coefficient x subscript = 3 x 1 = 3 atoms

2.Number of O atoms in C 2 H 5 OH = ____

O atoms in C 2 H 5 OH = ____ no. of O atoms = coefficient x subscript = 1 x 1 = 1 atom

3.Number of H atoms in C 2 H 5 OH = ____

H atoms in C 2 H 5 OH = ____ no. of 1 st H atom = coefficient x subscript = 1 x 5 = 5 atoms no. of 2 nd H atom =coefficient x subscript = 1 x 1 = 1 atom H atoms in C 2 H 5 OH = 6 atoms

4. Number of N atoms in 3AgNO 3 = ____

N atoms in 3AgNO 3 = ____ no. of N atoms = coefficient x subscript = 3 x 1 = 3 atoms

5.Number of O atoms in 2H 2 O = ____

O atoms in 2H 2 O = ____ no. of O atoms = coefficient x subscript = 2 x 1 = 2 atoms

6.Number of O atoms in Al 2 (SO 4 ) 3 = ____

O atoms in Al 2 (SO 4 ) 3 = ____ no. of O atoms = coefficient x subscript = 1 x {4 x 3} = 12 atoms

7.Number of S atoms in Al 2 (SO 4 ) 3 = ____

S atoms in Al 2 (SO 4 ) 3 = ____ no. of S atoms = coefficient x subscript = 1 x {1 x 3} = 3 atoms

8.Number of P atoms in 2Ca 3 (PO 4 ) 2 = ____

P atoms in 2Ca 3 (PO 4 ) 2 = ____ no. of P atoms = coefficient x subscript = 2 x {1 x 2} = 4 atoms

9.Number of Ca atoms in 2Ca 3 (PO 4 ) 2 = ____

Ca atoms in 2Ca 3 (PO 4 ) 2 = ____ no. of Ca atoms = coefficient x subscript = 2 x 3 = 6 atoms

10.Number of O atoms in H 2 O = ____

O atoms in H 2 O = ____ no. of O atoms = coefficient x subscript = 1 x 1 = 1 atom

1. 2Cu + O 2  2CuO REACTANTS PRODUCTS L.H.S. R.H.S. 2Cu + O 2  2CuO Cu = O =

1. 2Cu + O 2  2CuO REACTANTS PRODUCTS L.H.S. R.H.S. 2Cu + O 2  2CuO Cu = 2 x1=2 Cu = 2x1=2 O = 1x2 = 2 O = 2x1=2

2. CH 4 + 2O 2  CO 2 + 2H 2 O REACTANTS PRODUCTS L.H.S. R.H.S. CH 4 + 2O 2  CO 2 + 2H 2 O C = C = H = H = O = O =

2. CH 4 + 2O 2  CO 2 + 2H 2 O REACTANTS PRODUCTS L.H.S. R.H.S. CH 4 + 2O 2  CO 2 + 2H 2 O C = 1x1 = 1 H = 1x4 = 4 H = 2x2 = 4 O = 2x2 = 4 O = (1x2) + (2x1) = 4

1. Matter is neither created nor destroyed. 2. Atoms are rearranged in a chemical equation. 3. The number of atoms in the reactants is equal to the number of atoms in the products. STAAR Need to Know145

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Protons Positive + Neutrons Neutral Electrons Negative - STAAR Need to Know149

cm electrons protons neutrons cm STAAR Need to Know150 nucleus

Inside the Nucleus Protons with a Positive charge AND Neutrons with a Neutral charge – that means they do not have a charge Outside the Nucleus- in electron cloud Electrons with a Negative charge Did you know electrons are very, very small and move very, very fast??? STAAR Need to Know151

The periodic square for an element can tell you lots of information about that atom. Atomic number = # of protons Atomic number = # of electrons That means in a neutral (uncharged) atom the # of protons and electrons are always the SAME!!!! STAAR Need to Know152 11Na22.99

11Na Atomic Number or Protons Symbol Atomic Mass or Protons + neutrons

Atomic number = # of Protons = # of Electrons A=P=E STAAR Need to Know154

mass number M - atomic number - A # of neutrons N STAAR Need to Know155

The number of protons and neutrons in an atom STAAR Need to Know156

A balanced atom is neutral The net overall charge is zero Number of protons = Number of electrons Atomic number = Number of protons Atomic number = Number of electrons STAAR Need to Know157

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protons + neutrons

PCES

Problem: What is the charge of an electron, and what can its mass be compared to?

Claim:

Scientific Explanation: An electron has a negative charge, and it has less mass than a proton. Nucleus is heavy.

Problem: Which sub atomic particles are found in the cloud surrounding the nucleus?

B. Electrons are found in the electron cloud. They are negatively charged.

Journal Entry – Select the correct answer and explain.

Case One

Problem: Describe the sub atomic particle is found in the center of the atom.

A. All sub atomic particles have mass. Neutron has no charge.

Case Two

A = P = E 36 = 36 = 36

A = P = E 36 = 36 = 36

M 84 - A - 36 N 48

PCES

Problem: Which element has 37 protons?

Claim:

Scientific Explanation: Rubidium has 37 protons, and 48 neutrons

A = P = E 37 = 37 = 37

M 85 - A - 37 N 48

A. 86 B. 222 C. 62 D. 21

Problem: What is the atomic mass of radon?

The atomic mass of Radon is 222.

Journal Entry – Select the correct answer and explain.

Case One

Problem: Which element has 5 electrons? A = P = E 5 = 5 = 5

A. The element is Boron. A = P = E 5 = 5 = 5

Case Two

A = P = E

The atomic number (number of protons) determines an elements identity.

PCES

Problem: Which element has 11 protons? How does its valence electron explain its reactivity?

Claim:

Flourine needs one electron to fill in its 2 nd energy level. {2,7}

Na has one valence electron that can be easily lost during a chemical reaction. This makes it highly reactive. {2, 8, 1}

Scientific Explanation: Reactivity of elements decreases as you go from left to right of the periodic table. Atomic no. of Na is 11.

Problem: What determines how reactive an element is?

Valence electrons determine how reactive an element is. They are on the outer most energy level and are the first to come within close range of another element’s atom.

Journal Entry – Case One Select the correct answer and explain.

Case One

Problem: Which elements belong to the same group?

A. Atoms 1 and 4 have six valence electrons. They both belong to group 16.

1 valence electron 2 valence electrons 3 valence electrons 4 valence electrons 5 valence electrons 6 valence electrons 7 valence electrons 8 valence electrons,ex cept Helium one or two valence electrons

Case Two

A. Sn and Rb belong to period 5

PCES

Metals Metalloids Nonmetals Group 18 is called Noble Gas. They do not react with other elements

1.Malleable (broken 1. not malleable into thin plates) (brittle, break easily) 2. Ductile (made into 2. not ductile thin wires 3. Good conductors 3. poor conductors of of heat and electricity heat and electricity 4. metallic shine 4. no (rarely) metallic or luster shine or luster 5. Easily looses 5. easily gains electrons electrons

Problem: What is the location of the pale brittle yellow element that does not conduct electricity?

Claim:

Scientific Explanation: C Element at location C is a non metal. Non metals are brittle and do not conduct electricity?

Problem: Which elements have properties of both metals and non metals?

Scientific Explanation: Metalloids are located in the zig-zag portion of the periodic table.

Journal Entry – Case One Select the correct answer and explain.

Problem: Which element is shiny, solid at room temperature with two valence electrons?

G. The element is a metal – Strontium.

Case Two

Problem: Which element is a metal?

C. Mg has atomic number 12. It is a metal.

2H 2 O COEFFICIENT SUBSCRIPT

1. The coefficient gets applied to the ENTIRE formula 2.Coefficient = number of molecules 3. This means that there are 2 molecules of water.

4. The subscript only gets applied to the element it follows. 5. H = 2 x 2 = 4 atoms O = 2 x 1 = 2 atoms 6. total atoms = 6 atoms

How many hydrogen atoms are present? 4 How many oxygen atoms are present? 2

PCES

Problem: In which compound are there twice as many oxygen atoms?

Claim:

Scientific Explanation: G H 2 SO 4 number of atoms=coefficient x subscript H 2 = 1 x 2 = 2 O 4 = 1 x 4 = 4

Na 2 SO 4 S atoms = coefficient x subscript = 1 x 1

Journal Entry – Case One Select the correct answer and explain.

C 10 H 12 N 2 O C = 1 x 10 = 10 H = 1 x 12 = 12 N = 1 x 2 = 2 O = 1 x 1 = 1 Total = 25 atoms

Case Two

A new substance is produced. This means a chemical reaction has taken place.

P = precipitate or residue E = endothermic (heat is absorbed) or exothermic (heat is released) C = color change is unexpected S = smell, odor B = bubbles, fizz, gas released

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252 Elements with similar properties are placed in the same group in the periodic table. The stair-step line separates the elements into metals and nonmetals.

STAAR Need to Know253

254 ElementProtonsNeutronsElectrons 2 elements with similar properties Chlorine F and Br Iron-56 Magnesium-24 Lead-208 Nitrogen Ru and Os 12 Ca and Sr Sn and Ge P and As

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257 Combination of two or more pure substances. Substances are mixed together but have not reacted to form any new molecules. Example- Sugar (a compound) dissolves in water (a compound) to form a mixture. The molecules of sugar and water do not change chemically. They just become mixed together.

 Compounds that includes carbon along with other element(s) hydrogen, nitrogen, phosphorous, and or sulfur.  Nucleic Acid (DNA), Carbohydrates, Proteins, & Starch. STAAR Need to Know258

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260 Properties of matter Physical properties – can be observed without changing the substance into a different substance.

STAAR Need to Know261 Characteristics of a substance that are observed when it reacts (changes) to produce one or more different substances. Example- Water can be changed into hydrogen gas and oxygen gas using an electric current. When water molecules change chemically into hydrogen gas and oxygen gas, we say that a chemical change has occurred. Hydrogen gas and oxygen gas each have a different set of properties. Substances change into different substances through chemical reactions.

STAAR Need to Know262 Substances change into other substances in chemical reactions. The atoms in the original substance are rearranged. The bonds in the original substance may be broken and new bonds may be formed between different atoms. This produces one or more new substances that may be either pure elements or compounds. The products of a chemical reaction always have difference chemical and physical properties than the original substance(s).

 a change in odor,  a change in color,  a solid precipitate is formed,  a gas is formed,  there is either absorption (Endothermic) or release (Exothermic) of heat STAAR Need to Know263

P = precipitate or residue E = endothermic (heat is absorbed) or exothermic (heat is released) C = color change is unexpected S = smell, odor B = bubbles, fizz, gas released

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