CHEM 103 Lecture Notes - Lecture 4: Chemical Substance, Formula Unit, Magnesium Chloride

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12 Sep 2016

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7 li mass 7. 016 92. 58% atom are 7 li. 6 li mass 6. 015 --- 7. 42% atom are 6 li. 6. 015x. 0742+7. 016x. 9258=6. 942u - which is about the mass of li in the periodic table 6. 941u. Groups have family names because their properties are similar. Groups number tells us how many electron are in the atom"s outer shell. Period number tells us how many electron energy level that there are. Alkali metals element in group 1 (1a) have only 1 electron in the outer energy level. Halogen element in group 17 have 7 electrons in the outer energy level. Noble gases element in group 18, outer level are always filled. A monatomic ion is single atom that has gained or lost electrons. Ex: sodium atom = 11e- sodium + ions = 10e- + e- Ex: chlorine atom = 17e- + e- chloride- ion = 18e- Ionic compounds are neutral, meaning they have no net charge.

Related Questions

1)The NaCl2 ionic salt does not exist. Which of the followingstatements best explains why?

A. Because the formation of Na2+ is an unfavorable process due tothe great amount of energy required to remove the 2nd electron fromthe Na atom (the 2nd electron would have to be removed from thecore electrons of the Na atom).
B. Because the Cl- anion is too large for there to be two of themattached to one Na+ ion.
C. Because NaCl2 is actually a polyatomic ion with a -1 charge, andnot an ionic salt. In the presence of another Na+ ion, the Na2Cl2salt would form.
D. Because Cl2 has no charge and therefore would not be attractedelectrostatically to the positively charged Na2+ cation.

2)Select the false statement below.

A. The first ionization energy of an atom is smaller than thesecond ionization energy of the same atom.
B. Phosphorus has a greater first ionization energy than magnesium,and the reason for this is because P has a greater effectivenuclear charge (Zeff) than Mg.
C. The following process is an endothermic process and representsthe first ionization energy of an atom A:A(g) ? A1+(g) + e1-
D. Fluorine has a greater first ionization energy than iodine, andthe reason for this is because fluorine has a greater amount ofshielding of outer electrons by inner electrons than doesiodine.

3)The Group 5A elements N,P,As have lower (less negative) electronaffinities than most of the Group 4A or Group 6A elements becauseN,P,As have half-filled subshells.

True
False

4)A fluorine atom is smaller than a bromine atom, and a potassiumatom is larger than a lithium atom.

True
False

5)A certain main-group element exhibits the following successiveionization energies in kJ/mol:

IE1 = 100; IE2 = 1200; IE3 = 2300; IE4 = 3100; IE5 = 4200

Select the false statement about this element below.

A. This is likely a Group 1A element.
B. This element is typically found uncombined in nature (that is,it is not usually found in compounds, but rather as a freeelement).
C. If this element is given a symbol of "J", it would form an ioniccompound with sulfur as J2S.
D. If this element was in period 2 of the periodic table, it wouldbe lithium.

6)Select the false statement below.

A. Generally speaking, non-metallic elements have greater effectivenuclear charge (Zeff) than metallic elements in the sameperiod.
B. Generally speaking, as you go down a group in the periodictable, there is successively greater shielding of the outer-shellelectrons by the inner-shell electrons.
C. Generally speaking, the heavier alkali metals can be predictedto exhibit greater shielding of the outer-shell electrons by theinner-shell electrons than lighter alkali metals.
D. Generally speaking, as you go across a period in the periodictable, the effective nuclear charge (Zeff) decreases because eachsuccessive element contains more protons in the nucleus than theprevious element and the outer electrons are all in the same shellas you go across a period.

7)Place the following in order of increasing size:

O2-, F1-, Li1+

A. F1- < Li1+ < O2-
B. Li1+ < O2- < F1-
C. Li1+ < F1- < O2-
D. F1- < O2- < Li1+

8)Select the false statement below.

A. The following set of quantum numbers is allowed:
n = 4, l = 2, ml = -2, ms = +1/2
B. The n = 1 shell of any given atom can accomodate up to 2electrons.
C. The n = 4 shell of any given atom can accomodate up to 16electrons.
D. In any given atom, the l = 2 subshell can accomodate up to 5electrons that have negative spins (ms =

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Question 1 of 15 (worth 2 points)
The NaCl2 ionic salt does not exist. Which of the followingstatements best explains why?

A. Because the formation of Na2+ is an unfavorable process due tothe great amount of energy required to remove the 2nd electron fromthe Na atom (the 2nd electron would have to be removed from thecore electrons of the Na atom).
B. Because Cl2 has no charge and therefore would not be attractedelectrostatically to the positively charged Na2+ cation.
C. Because NaCl2 is actually a polyatomic ion with a -1 charge, andnot an ionic salt. In the presence of another Na+ ion, the Na2Cl2salt would form.
D. Because the Cl- anion is too large for there to be two of themattached to one Na+ ion.
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 2 of 15 (worth 2 points)
Select the false statement below.

A. Fluorine has a greater first ionization energy than iodine, andthe reason for this is because fluorine has a greater amount ofshielding of outer electrons by inner electrons than doesiodine.
B. The following process is an endothermic process and representsthe first ionization energy of an atom A:
A(g) ? A1+(g) + e1-

C. Phosphorus has a greater first ionization energy than magnesium,and the reason for this is because P has a greater effectivenuclear charge (Zeff) than Mg.
D. The first ionization energy of an atom is smaller than thesecond ionization energy of the same atom.
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 3 of 15 (worth 2 points)
The following process represents the first electron affinity of anatom A:

A(g) ? A1+(g) + e1-

True
False
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 4 of 15 (worth 2 points)
Generally speaking, most nonmetal atoms are smaller than most metalatoms.

True
False
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 5 of 15 (worth 2 points)
A certain main-group element exhibits the following successiveionization energies in kJ/mol:

IE1 = 100; IE2 = 1200; IE3 = 2300; IE4 = 3100; IE5 = 4200

Select the false statement about this element below.

A. If this element is given a symbol of "J", it would form an ioniccompound with sulfur as J2S.
B. This element is typically found uncombined in nature (that is,it is not usually found in compounds, but rather as a freeelement).
C. This is likely a Group 1A element.
D. If this element was in period 2 of the periodic table, it wouldbe lithium.
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 6 of 15 (worth 2 points)
Select the false statement below.

A. Generally speaking, as you go down a group in the periodictable, there is successively greater shielding of the outer-shellelectrons by the inner-shell electrons.
B. Generally speaking, non-metallic elements have greater effectivenuclear charge (Zeff) than metallic elements in the sameperiod.
C. Generally speaking, the heavier alkali metals can be predictedto exhibit greater shielding of the outer-shell electrons by theinner-shell electrons than lighter alkali metals.
D. Generally speaking, as you go across a period in the periodictable, the effective nuclear charge (Zeff) decreases because eachsuccessive element contains more protons in the nucleus than theprevious element and the outer electrons are all in the same shellas you go across a period.
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 7 of 15 (worth 2 points)
Place the following in order of increasing size:

O2-, F1-, Li1+

A. F1- < O2- < Li1+
B. F1- < Li1+ < O2-
C. Li1+ < O2- < F1-
D. Li1+ < F1- < O2-
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 8 of 15 (worth 2 points)
Select the false statement below.

A. The n = 4 shell of any given atom can accomodate up to 16electrons.
B. In any given atom, the l = 2 subshell can accomodate up to 5electrons that have negative spins (ms =

I am doing the Atomic Mass of Metallo

You may have noticed on the periodic table that the atomic mass of an element is usually not a whole number. That happens because of isotopes. An atom that is missing a neutron or has an extra neutron is called an isotope. They are still the same element; however, they are just a little different from every other atom of the same element.

Most of the carbon atoms in the universe are Carbon-12, with 6 neutrons. A small percentage of carbon atoms are Carbon-13, with 7 neutrons, and an even smaller percentage are Carbon-14 and have 8 neutrons. Carbon-13 and Carbon-14 are isotopes of carbon.

Atomic mass is calculated by determining how many atoms of each isotope type are present in the universe. Since the isotopes of carbon make up only a small percentage of the carbon in the universe, the average of the masses of all carbon atoms is slightly higher than 12, so the atomic mass for carbon is actually 12.011.

Objective

Analyze the isotopes of âMetalloâ and to calculate its atomic mass

Materials

sample of metallo (bag of mixed nuts, bolts, and washers)

balance

Procedures

Obtain a sample of the new element âMetallo.â

Separate the three isotopes of Metallo (nuts, washers, bolts) and measure the mass of each isotope.

Count the numbers of each isotope.

Record all data in the table.

Data Table

	Nuts	Bolts	Washers	Totals
Total Mass (g)
Number

Average Mass (g)
Percent Abundance
Relative Abundance
Relative Mass

Analysis

Calculate the average mass of each isotope by dividing the total mass by the number of particles of that isotope. Record your answers on the Data Table.

Calculate the percent abundance of each isotope by dividing its number of particles by the total number of particles and multiplying by 100. Record your answers on the Data Table.

Calculate the relative abundance of each isotope by dividing the percent abundance from Step 2 by 100. Record your answers on the Data Table.

Calculate the relative mass of each isotope by multiplying its relative abundance from Step 3 by its average mass. Record your answers on the Data Table.

Calculate the average mass of all Metallo particles by adding the relative masses. This average mass is the atomic mass of Metallo.

Explain the difference between percent abundance and relative abundance. What is the result when you total the individual percent abundances? The individual relative abundances?

The percent abundance of each isotope tells you how many of each kind of isotope exist in every 100 particles. What does relative abundance tell you?

Compare the total values for Rows 3 and 6 in the Data Table. Explain why the totals differ and why the value in Row 6 best represents the atomic mass.

CHEM 103 Lecture Notes - Lecture 4: Chemical Substance, Formula Unit, Magnesium Chloride

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