staar reporting category 1 matter & energy. atoms and elements

STAAR Reporting Category 1Matter & Energy

Atoms and Elements

The Structure of an Atom

nucleus++

+ ++

+

Proton (+)

neutron (o)

electroncloud

electron (-)

Location and Mass of Atomic Particles

Inside the Nucleus

Protons with a POSITIVE

charge

AND

Neutrons with a NEUTRAL charge (no charge)

Both have about the same mass

Outside the Nucleus

Electrons with a NEGATIVE charge

VERY, VERY tiny and do not contribute to the mass of the atom

It takes 2000 electrons to equal the mass of one proton or neutron

Elements are listed on thePeriodic Table

Atomic Number

Number of PROTONS and determine which element the

atom is

Atomic Mass

the number of PROTONS + NEUTRONS

First, round the atomic mass to the nearest whole number

Round to 28

How do I calculate # of NEUTRONS???

Then, subtract the Atomic number (# protons) from the Atomic mass (total # protons

and neutrons

28 (Atomic mass)

-14 (Atomic number) 14 NEUTRONS

Is there an EASIER way to remember all of this?

All you have to do is remember:

A=P=E

M-A=N

A=P=E

Atomic Number = Protons = Electrons

If I know ONE, I know them

ALL!!

M-A=NMass

-

Atomic Number

=

Neutrons

Symbol Atomic #

Mass #

#Protons

#Neutrons

#Electrons

He 2 4 2

3 7 3 3

N 7 7 7

PRACTICE TIMEUse your Periodic Table!!

Li

2 2

4

7 14

Electrons and Bohr Diagrams

1) Find your element on the periodic table.

2) Determine the number of electrons – remember, it is the same as the atomic number.

3) This is how many electrons you will draw.

Bohr Diagrams

6 P6 N6 P6 N

Draw a nucleus with the number of protons and neutrons inside.

Bohr Diagrams

1) Add the electrons.

2) Carbon has 6 electrons.

3) The first shell can only hold 2 electrons. Always start in the first shell

6 P6 N6 P6 N

Bohr Diagrams1) Since you have 2

electrons already drawn, you need to add 4 more.

2) These go in the 2nd shell.

6 P6 N6 P6 N

Bohr Diagrams1) Check your work.

2) You should have 6 total electrons for Carbon.

3) Only two electrons can fit in the 1st shell.

4) The 2nd and 3rd shells can hold up to 8 electrons.

6 P6 N6 P6 N

Bohr Diagrams

Try the following elements on your own:

a) H

b) He

c) O

d) Al

e) Ne

f) K

Bohr Diagrams


a) H – 1 electron

b) He

c) O

d) Al

e) Ne

f) Na

1 P1 P

Bohr Diagrams


a) H

b) He - 2 electrons

c) O

d) Al

e) Ne

f) Na

2 P2 N2 P2 N

Bohr Diagrams


a) H

b) He

c) O - 8 electrons

d) Al

e) Ne

f) Na

8 P8 N8 P8 N

Bohr Diagrams


a) H

b) He

c) O

d) Al - 13 electrons

e) Ne

f) Na

13 P14 N13 P14 N

Bohr Diagrams


a) H

b) He

c) O

d) Al

e) Ne - 10 electrons

f) Na

10 P10 N10 P10 N

Bohr Diagrams


a) H

b) He

c) O

d) Al

e) Ne

f) Na - 11 electrons

11 P12 N11 P12 N

Valence Electrons

• Found on the outermost energy level

–Determine how an element will react chemically

Lewis Structures

How many valence electrons does nitrogen

have?

5

Learning Check

How many valence electrons in each atom?

Helium

Oxygen Sodium

2 6 1

Charges of Atoms

Most atoms have a NEUTRAL CHARGE since they have equal numbers of protons (+) and electrons (-).

Some atoms gain or lose electrons to become IONS.

IONS are not neutral and the atom becomes positively or negatively charged. Let’s see how this works...

++

++

+

in an atom,protons ( ) are inthe centerand electrons ( )are on the outside

+

++

++

+

only electrons ( )can be addedor taken away

++

++

+

this is an atom with5 electrons and

5 protons

++

++

+

the atom is neutral

net charge = zero

5 (-) and 5 (+) = zero charge (neutral)

++

++

+

6 (-) and 5 (+) = -1

charge = ?

++

++

+

3 (-) and 5 (+) = +2

charge = ?

WHEN REMOVING ELECTRONS

THE RESULTING CHARGE IS POSITIVE

neutral +1

THE RESULTING CHARGE IS NEGATIVE

neutral -2

WHEN ADDING ELECTRONS

Elements are substances:

• that cannot be broken down into other substances

• that are made of atoms with the same number of protons in the nucleus

Elements are ORGANIZED on the Periodic Table

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.

Groups of ElementsGroups of Elements

Alkali Metals

• Group 1, highly reactive, 1 valence electron

• Soft metals with low melting points

The Periodic Table of Elements

1 18

1 H 2 13 14 15 16 17 He2 Li Be B C N O F Ne3 Na Mg 3 4 5 6 7 8 9 10 11 12 Al Si P S Cl Ar4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe6 Cs Ba Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn7 Fr Ra Lr Rf Db Sg Bh Hs Mt Ds Rg

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm YbAc Th Pa U Np Pu AmCm Bk Cf Es Fm Md No

Alkaline Earth Metals

• Group 2, reactive, 2 valence electrons

• Hard metals with high melting points


1 18



Transition Metals

• Group 3-12, variable # of valence electrons

• Unpredictable, don’t follow “reactivity” rules


1 18



Halogens

• Group 17, highly reactive, 7 valence electrons

• Form “salts”

The Periodic Table of Elements1 18



Noble Gases

• Group 18, full outer shells (2 in He and 8 in others)

• NON-REACTIVE




Rare Earth Elements • Group 3, Period 6 and 7• Special group of transition metals• Many are synthetic and/or radioactive




Metalloids

• Non-metal elements that are conductors of heat and electricity




Periodic Trends• Elements are arranged into horizontal rows called

PERIODS• Elements within a period have the same number of

ENERGY LEVELSThe Periodic Table of Elements

1 18



1 energy level

2 energy levels

3 energy levels

7 energy levels

6 energy levels

5 energy levels4 energy levels

• Elements are arranged in vertical columns called GROUPS – have same number of VALENCE ELECTRONS – share similar CHEMICAL properties

4 va

len

ce e

lect

ron

s

6 va

len

ce e

lect

ron

s




2 va

len

ce

elec

tron

s

1 va

len

ce e

lect

ron

3 va

len

ce e

lect

ron

s

5 va

len

ce e

lect

ron

s

7 va

len

ce e

lect

ron

s

8 va

len

ce e

lect

ron

s

Metal Properties• Shiny solids

• Ductile (able to be stretched)

• Malleable (able to be shaped)

• Good conductors of heat and electricity

• Magnetic

Nonmetal Properties• May be solids, liquids or gases

• Dull, brittle solids

• Poor conductors of heat and electricity

• Non-magnetic

Metalloid Properties

• Nonmetals with properties of both metals and non-metals• Weak conductors of heat and electricity

Atomic Theory

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- H2O )

Writing Chemical Symbols

1. First letter is capitalized

2. Second letter is lower case

3. NO period at the end

H Cl O Hg Fe Sn C He

Co or CO

Does it really matter?

Alloys for metals used in jet turbines

Co = cobalt

carbon monoxide ColorlessOdorlessPoisonous gas

carbon oxygen

COCompound

Compounds2 or More Elements

Chemically Combined

Oxygen

Hydrogen Hydrogen2-H: 1-O

Water

HH

O

Ratio 2:1

Formulas use element symbolswith subscript numbers

H2O

1 is notshown

Change the ratioChange the substance

2:2

H2O2

Subscript numbers

http://www.wonderquest.com/images/2003-08-08-peroxide.jpg

HydrogenPeroxide

http://www.wonderquest.com/images/2003-08-08-peroxide.jpg

No subscripts??

NaCl1Na 1Cl

How many elements?

Salt

2

Chemical Changes

A chemical change is a change in which both the physical and chemical properties of the original substance are changed. The new substance has new physical and chemical properties.

Burning is a chemical change.

A chemical change is the result of a Chemical Reaction.

A chemical reaction occurs when atoms separate, come together, or rearrange to form new substances with new properties.

Example of a Chemical Reaction

Reactant + Reactant Product (goes to)

carbon + oxygen carbon dioxide (has different properties)

C + O2 CO2

Is the product the same as the reactants?

No, the atoms have been rearranged.

For Example…A chemical reaction takes place during

photosynthesis.

6CO2 + 6H2O C6H12O6 + 6O2

Carbon dioxide reacts with water to form glucose (a sugar) and oxygen.

copper + oxygen copper oxide 2 Cu O2 2 CuO

Cu O CuO

Cu O CuO

balanced

2 copper atoms 2 copper atoms

2 oxygen atoms 2 oxygen atoms

in a molecule (O2)

2 copper atoms 2 copper atoms=balanced=

2 oxygen atoms 2 oxygen atoms

Since nothing is lost or gained, there is no loss or gain in mass (atoms).

You can say the equation is balanced.

The Law of conservation of mass states that matter cannot be created or destroyed in any chemical reaction

The atoms in the reactants are rearranged to form new compounds, but none of the atoms disappear, and no new atoms are formed.

HH

HH O O

Reactants Products

Remember that atoms don’t change in a chemical reaction.

• The number and kinds of atoms present in the reactants of a chemical reaction are the same as those present in the products. When stated this way, it becomes the law of conservation of atoms.

So: Chemical equations are balanced, when the numbers and kinds of atoms on each side of the reaction arrow are equal.

H

H

HH O O

Reactants Products

HH

HH

OO

4 Hydrogen 4 Hydrogen

2 Oxygen 2 Oxygen

Coefficients, the numbers placed in front of formulas to balance equations, indicate the number of particles present in the reaction. If a number is not present it is understand that 1 is the coefficient. 2 H2 + O2 2 H2O

2

Notice that the number of hydrogen and oxygen atoms are equal

2

The number of oxygen atoms are not the same so the equation is balanced with coefficients.

The same number of each kind of atom must be on the left side of the arrow as are on the right side when an equation is balanced.

Al Al

Al Al

O O

O OO O

AlAlAlAl

O OO O

O O

When an equation is balanced the number of reactant atoms will always equal the number of product atoms and atoms are conserved

Al AlOO O

Al AlOO O

Chemical Equations• Many times it may seem that things we use disappear

over time. For example, gasoline in the car.• Elements of gasoline are merely re-arranged through

a chemical reaction. Gasoline CO2 and H2O• The number of each type of element and their masses

remain unchanged (balanced) in a chemical reaction. (Law of Conservation of Mass)

• A chemical equation is a way to describe or represent what goes on in a chemical reaction and follows the Law of Conservation of Mass.

• Matter cannot be created or destroyed – ONY rearranged into different substances.

Chemical and Physical Change

Organic Compounds

• Compounds that includes CARBON along with other element(s) hydrogen, nitrogen, phosphorous, and or sulfur.

• Nucleic Acid (DNA), Carbohydrates, Proteins, & Starch.

Is it Organic?C6H12O6

Ca3Si2O7

NaCl

C3H8

Fe2O3

YES

no

no

YES

no

C5H11NO2S

CuSO4

CH3COOH

Ca5(PO4)3OH

C27H46O

YES

no

YES

no

YES

The transfer of energy from the sun to producer to primary consumer to

secondary consumer to tertiary consumer can be shown in a FOOD

CHAIN.

The arrow shows the flow of energy, first from the sun to the producers

and then to each organism in the food chain.

Food Webs:

• Are interconnected food chains

• They show the feeding relationships in an ecosystem

• Arrows point in direction of energy flow

Another way of showing the transfer of energy in an ecosystem is the

ENERGY PYRAMID.

Energy pyramids show • That the amount of available

energy decreases down the food chain

• Only 10 % of the energy is passed to the next level

• It takes a large number of producers to support a small number of primary consumers

• It takes a large number of primary consumers to support a small number of secondary consumers

100%

10%

1%

.1%

What is density?

• Density is a comparison of how much matter there is in a certain amount of space.

What is density?

• Density = mass OR mass ÷ volume.

volume

• Units for density: g

cm3

OR

g

mL

ALWAYS REMEMBER UNITS!

Density Problems• Frank has a paper clip. It has a mass of 9 g and a

volume of 3 cm3. What is its density?

• Frank also has an eraser. It has a mass of 3 g, and a volume of 1cm3. What is its density?

D = m v

D = 9 g

3 cm3D = 3 g/cm3

D = m v

D = 3 g

1 cm3D = 3 g/cm3

• Jack has a rock. The rock has a mass of 6 g and a volume of 3 cm3. What is the density of the rock?

• Jill has a gel pen. The gel pen has a mass of 8 g and a volume of 2 cm3. What is the density of the pen?

D = m v

D = 6 g

3 cm3D = 2 g/cm3

D = m v

D = 8 g

2 cm3D = 4 g/cm3

• Al’Licia has a watch. It has a mass of 4 g and a volume of 2 cm3. What is the density of the watch?

• Mia has a wallet. It has a mass of 15 g and a volume of 5 cm3. What is the density of the wallet?

D = m v

D = 4 g

2 cm3D = 2 g/cm3

D = m v

D = 15 g

5 cm3D = 3 g/cm3

√ Check yourunderstanding

Use your

Periodic

Table

1. The symbol for carbon is –

A Ca

B c

C CA

D C

2. How many protons are in an atom of sodium?

A 11

B 12

C 23

D 34

3.How many neutrons are there,if the mass number is 1 andthe atomic number is 1?

A 3

B 2

C 1

D 0

4.How many electrons are inan atom of Cl?

A 17

B 18

C 35

D 0

5.Which of the following isa chemical formula?

A H

B O

C H2O

D h2o

6.How many different elements are in baking soda, NaHCO3 ?A 6

B 5

C 4

D 3

7. Which of the following situations contains an example of a chemical reaction?

A Ice forming after water is placed in a freezer

B Watercolor paint drying on paper

C A sugar cube dissolving in a glass of water

D A bicycle rusting after it is left in the rain

C6H12O6 + 6 O2 6 H2O + 6 CO2

HCl + NaOH H2O + NaCl

8. Based on the data above, which statement is not true about chemical equations?

A. Products are the rearrangement of atoms from the reactants.

B. There are always more atoms on the reactant side of the equation than the product side.

C. The types of atoms in the products will be the same as the types of atoms in the reactants.

D. The mass and number of reactant atoms always equals the mass and number of product atoms.

9. Which chemical reaction is balanced?

A. C + O2 2 CO2

B. 2 C + O2 2 CO2

C. 2 C + 2 O2 2 CO2

10. Which chemical reaction is balanced?

A. HBr + Mg H2 + MgBr2

B. 2 HBr + Mg H2 + MgBr2

C. 2 HBr + 2 Mg H2 + 2 MgBr2

staar reporting category 1 matter & energy. atoms and elements

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