Group 3: Exercises

Find the Accuracy and Sensitivty of the followeing measuring devices:
  


 0                  1                 2                  3                4 1. Accuracy:
    Sensitivity:




 0                    10               20                 30               40        2. Accuracy :

        Sensitivity:




.001          .002            .003             .004           .005       3. Accuracy:

       Sensitivity:





.67             .68               .69              .70               .71      4. Accuracy:
 ______________________                                               Sensitivity:

What is the measurment of the thin pink line?

Sub-Atomic Particles

 What are the atoms made of?

 We all know that particles makes up an atom. These particles are called, "Subatomic Particles." Subatomic particles are particles smaller than the atom. There are three subatomic particles that form an atom namely: the protons, neutrons and electrons. The center of the atom is called the nucleus. 

To further learn about subatomic particles, let's discuss each and every particle inside the atom.

PROTONS

All protons are identical to each other. They also have a positive electrical charge, so they're always represented with a plus (+) sign.It is found inside the nucleus of an atom, together with the n. So, therefore, both of them are called nucleons of an atom. 

Note! The number of protons in the nucleus determines the chemical properties of the atom and thus which chemical element is represented.

NEUTRONS 

 

 Like protons, neutrons are also identical to each other, but its mass is slightly larger than that of a proton.They have no electrical charge and are said to hold the protons together (protons are positively charged particles and should repel each other.) Neutrons are nucleons, thus found inside the nucleus. 

Note!  

• The number of neutrons and protons inside an atom gives the atoms their specific characteristics. One would know that one element is different from the other based on the number of their nucleons.  
• The number of neutrons is the neutron number and determines the isotope of the element.  

 ELECTRONS

Electrons are the negatively charged particles of atoms. Together, all of the electrons of an atom create a negative charge that balances the positive charge of the protons in the atomic nucleus. Electrons are extremely small compared to all of the other parts of the atom. The mass of an electron is almost 1,000 times smaller than the mass of a proton. 

Electrons are found in the clouds that surround the nucleus of an atom. They are located in what scientists called shells. These shells change depending on the number of electron in an element has. The higher the atomic number, the more shells and atoms the element has. 

Note! 

•  Represented by a minus (-) sign, in reference to its negative charge.
• Plays a major role in many chemical bonds.
• Electrons are sometimes shared between 2 or more atoms in a cloud.   

 

 Terms and Methods to Determine an Element

Atomic Number (aka proton number)

The number of protons found in the nucleus of an atom. It uniquely identifies an element. Remember that in a neutral charge, the number of protons is equal to the number of electrons. It is usually represented by the letter, Z. 


Atomic Mass 
Atomic mass is defined as the number of protons, electrons and neutrons in a single atom. Often represented by the letter, A. 

AZPEN

• A - Atomic Mass
• Z - Atomic Weight
• P - Number of protons
• E - Number of electrons
• N - Number of neutrons 
  

Isotopes 
Atoms of the same element can have different number of neutrons, the different possible versions of each element is called isotopes. 

If you want to write a certain isotope you write it like this: ^AX<sub>Z with X representing the symbol of the element, A as the number of neutrons and protons combined and Z as the atomic number. 

For example, the element hydrogen is known to have no neutrons, but there is an isotope of hydrogen containing one neutron (deuterium) and with two neutrons (tritium.)</sub> 

  

Ions

An ion is an atom or molecule in which the total number of electrons is not equal with the total number of protons, giving it a positive or negative electric charge.

Two Kinds of Ions

• Anion - an ion with more electrons than protons, giving it a negative charge.
• Cation - an ion with a less number of electrons than that of protons, giving it a net positive charge. 

Ionic Bonding

- a kind of chemical bonding that arises from the mutual attraction of oppositely charged ions. Since ions of like charge repel each other, they do not usually exist on their own. Instead, many of them may form a crystal lattice, in which ions of opposite charge are bound to each other. The resulting compound is called an ionic compound, and is said to be held together by ionic bonding.

How Ions Gain or Lose Charges

 Ions gain charges through ionization. Ionization is the process by which an electrically neutral atom, molecule, or radical loses or gains one or more electrons and becomes an ion. Ionization can occur in gases, liquids, or solids. Physicists often call a highly ionized gas a plasma.

 

EXERCISES!
Identification.

1. The meaning of the acronym "AZPEN." 
2. What do you call the ion with less number of electrons than that of the protons? What is its charge?
3. What are the three sub-atomic particles? What are their charges?
4. What sub-atomic particle plays a major role in chemical bonding? 
5. What do you call atoms or molecules with different numbers of electrons?
6. What are the two sub-atomic particles located inside the nucleus?
7. What do you call atoms of the same element, but with different numbers of neutrons?
8. Other term for atomic number.
9. What determines the chemical properties of an atom?
10. Explain ionization.  

GROUP 5

Burton, Danielle

Gaite, Aika

Lozada, Marcia

Pentinio, Arra

Santos, Patricia

2 - 10

\m/ 

 

Accuracy and Sensitivity of Measuring Devices

Accuracy and Sensitivity


1. Accuracy 

• refers to the agreement between experimental data and a known value.
• how close to the actual or true accepted value are the measurement
• you can think of it in terms of a bulls-eye in which the target is hit close to the center, yet the marks in the target aren't necessarily close to each other.

2. Precision

• refers to how well experimental values agree with each other
• how close are the individual measurements to one another
• if you hit a bulls-eye precisely, then you are able to hit the same spot on the target each time, even though that spot may be distant from the center

3. True Value

• a given measurement that is set by the experts (i.e. scientists, professors, etc.)

4. Experimental Value

• the value gathered by the performer

How to Compute For The Percent Error

% Error=(True Value-Experimental Value)
                                 TV                       X100


Exercises
1. While doing an experiment, you were asked to measure a square block that was given to you. Each side was 15.72 cm. In your 3 trials you got: 15.23 cm , 14.92 cm  & 15.57 cm, an average of 15.24 cm. Find the percent error.


=(15.72-15.24)/15.72 X 100
=o.48/15.72X100
=o.0305X100


% error=3.05%


2. In an experiment, you were asked to find out the measurement of a liquid inside the glass beaker. You had 3 trials in which you got: 25.32 ml, 27.45 ml & 26.24, having an average of 26.34 ml. The true value was 27.50 ml. Find the percent error.


=(27.50-26.34)/27.50 X 100
=1.16/27.50 X 100
=o.0422X100


% error= 4. 22%


3.  You were inside a pet store when you saw puppies. You had estimated that there were 14 of them, though they were 15. Find the percent error.


=(15-14)/15 X 100
=1/15 X 100
= o. 0667X 100


% error= 6.67%


4. While walking outside your house, you saw pink petals scattered everywhere. You estimated that there were 50 of them, when there was 52 petals. Find the percent error.




=(52-50)/52 X 100
=2/52 X 100
=0.0385 X 100


% error= 3.85 %


5. While conducting an experiment, you were to measure a piece of block given to you. You had 4 trials to measure the block. You had arrived with these results: 14.25 cm, 14.26 cm, 14. 22 cm & 14. 23 cm. The true value was 14. 26 cm. What is your percent error?


=(14.26-14.24)/14.26 X 100
=o.o2/14.26 X 100
=0.0014 X 100


% error= 0.14 %


Members:
Cruz
Gonzales, I.
Mariano
Pineda
Sarmiento

Electron Distribution Mnemonics

 Electrons tend to arrange themselves around nuclei  so that they have the lowest possible energy. They would all like to get into the lowest energy level, sometimes called the K-shell, but are prevented from doing so by some rules that pop up in quantum mechanics. 




A mnemonic for the entire periodic table of the elements recalls the names and abbreviations of all the elements, their basic electron structures, and some properties. Elements are presented in chemically useful groupings with a method that allows one to position an element without recreating the entire table. With two additional lines one can derive all the major elements and the trace elements required by humans. Another verse identifies anomalies in orbital filling. 


An energy level  is a quantum mechanical system or particle that is bound, confined spatially, can only take on certain discrete values of energy, as opposed toclassical particles, which can have any energy. These values are called energy levels. The term is most commonly used for the energy levels of electrons in atoms or molecules, which are bound by the electric field of the nucleus. The energy spectrum of a system with energy levels is said to be quantized.

If the potential energy is set to zero at infinity, the usual convention, then bound electron states have negative potential energy.

Energy levels are said to be degenerate, if the same energy level is shared by more than one quantum mechanical state. They are then called degenerate energy levels.

An atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom. Atomic orbitals are the possible quantum states of an individual electron in the collection of electrons around a single atom, as described by the orbital function. Atomic orbitals exactly describe the shape of this atmosphere only when a single electron is present in an atom. When more electrons are added to a single atom, the additional electrons tend to more evenly fill in a volume of space around the nucleus so that the resulting collection (sometimes termed the atom’s “electron cloud”) tends toward a generally spherical zone of probability describing where the atom’s electrons will be found.

Each orbital is defined by a different set of quantum numbers and contains a maximum of two electrons. The simple names s orbital, p orbital, d orbital and f orbital refer to orbitals with angular momentum quantum number l = 0, 1, 2 and 3 

Each shell is composed of one or more subshells, which are themselves composed of atomic orbitals. For example, the first (K) shell has one subshell, called "1s"; the second (L) shell has two subshells, called "2s" and "2p"; the third shell has "3s", "3p", and "3d"; and so on.^[1]The various possible subshells are shown in the following table:

Subshell label	ℓ	Max electrons	Shells containing it	Historical name
s	0	2	Every shell	sharp
p	1	6	2nd shell and higher	principal
d	2	10	3rd shell and higher	diffuse
f	3	14	4th shell and higher	fundamental
g	4	18	5th shell and higher

• The first column is the "subshell label", a lowercase-letter label for the type of subshell. For example, the "4s subshell" is a subshell of the fourth (N) shell, with the type ("s") described in the first row.
• The second column is the azimuthal quantum number of the subshell. The precise definition involves quantum mechanics, but it is a number that characterizes the subshell.
• The third column is the maximum number of electrons that can be put into a subshell of that type. For example, the top row says that each s-type subshell ("1s", "2s", etc.) can have at most two electrons in it. In each case the figure is 4 greater than the one above it.
• The fourth column says which shells have a subshell of that type. For example, looking at the top two rows, every shell has an s subshell, while only the second shell and higher have a p subshell (i.e., there is no "1p" subshell).
• The final column gives the historical origin of the labels s, p, d, and f. They come from early studies of atomic spectral lines. The other labels, namely g, h and i, are an alphabetic continuation following the last historically originated label of f.

EXERCISES!!!

Electron Configuration Practice Worksheet

In the space below, write the unabbreviated electron configurations of the following elements:

1)  sodium  ____________________________________

2) iron  ___________________________________

3) bromine  ___________________________________

4) barium  _____________________________________

5) neptunium   _____________________________________

Determine what elements are denoted by the following electron configurations:

6)        1s²2s²2p⁶3s²3p⁴  ____________________

7)        1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s¹  ____________________

 8)      [Kr] 5s²4d¹⁰5p³  ____________________

 9)      [Xe] 6s²4f¹⁴5d⁶  ____________________

 10)     [Rn]  7s²5f¹¹  ____________________

Determine which of the following electron configurations are not valid:

11)         1s²2s²2p⁶3s²3p⁶4s²4d¹⁰4p⁵ ____________________

12)         1s²2s²2p⁶3s³3d⁵  ____________________

13)         [Ra] 7s²5f⁸  ____________________

14)         [Kr]  5s²4d¹⁰5p⁵ ____________________

15)         [Xe]  ____________________

Electron Configurations - Solutions

Note:  The electron configurations in this worksheet assume that lanthanum (La) is the first element in the 4f block and that actinium (Ac) is the first element in the 5f block.  If your periodic table doesn’t agree with this, your answers for elements near the f-orbitals may be slightly different.

1.    sodium            1s²2s²2p⁶3s¹

2.    iron                   1s²2s²2p⁶3s²3p⁶4s²3d⁶

3.    bromine           1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁵

4.    barium             1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²

^5.        neptunium      1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²4f¹⁴5d¹⁰6p⁶7s²5f⁵

6.    1s²2s²2p⁶3s²3p⁴  sulfur

7.    1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s¹  rubidium

8.    [Kr] 5s²4d¹⁰5p³  antimony

9.    [Xe] 6s²4f¹⁴5d⁶  osmium

10. [Rn]  7s²5f¹¹  einsteinium

11. 1s²2s²2p⁶3s²3p⁶4s²4d¹⁰4p⁵ not valid (take a look at “4d”)

12. 1s²2s²2p⁶3s³3d⁵  not valid (3p comes after 3s)

13. [Ra] 7s²5f⁸  not valid (radium isn’t a noble gas)

14. [Kr]  5s²4d¹⁰5p⁵ valid

15. [Xe]  not valid (an element can’t be its own electron configuration)

Members:(2-10)

Myka Bautista-Exercises

Nikki Ferrarez(Squid)-Research

Camille Lam

Joy Palag-Web Page Designer

Sandra Santos

Sources:

Wikipedia.com

Google.com

Special Thanks To:

God for giving me hope and patience.