Bonding Lab
Introduction:
The objective of this lab was to test the properties of six separate unknown substances (A, B, C, D, E, and F). Then, using these properties, determine whether each Unknown substance is covalently or ionically bonded.
To become completely stable, an atom must have eight valence electrons. Valence electrons are the electrons found only on the outer ring (or subshell) of an atom. Once an atom has obtained all eight electrons, it will take a very large amount of energy to remove one of these from the atom, as the atom is in it's most secure state. Atoms which have less than eight valence electrons are less stable, and may lose electrons more easily depending on the number of electrons the atom is from obtaining all eight valence electrons.
Atoms which have three or less valence electrons will 'want' to lose these electrons so they may acquire the stable eight electrons on the next subshell closer to the nucleus of the atom. When these electrons are lost, the atom will become a positive ion. This happens because there are both protons and neutrons in the nucleus, (protons are positive and neutrons are neutral) this causes the nucleus of an atom to be positive, as the neutrons do not contribute to the charge of the atom as they have a neutral charge. Electrons have a negative charge, therefore, when these are taken away from an atom, it becomes a positive ion because there are less electrons present to counteract the positive charge of the nucleus. Atoms which have five or more electrons will 'want' to gain electrons so the outer shell will have a full eight valence electrons. When this happens, the atom will become negative as the electrons are cancelling out the positive charge of the nucleus. When an atom has four valence electrons, it may either gain or lose electrons to become more stable, based on if it is a metal or non-metal. If the element is a metal, the atom will lose electrons, if the element is a non-metal, it will gain electrons. The number of electrons gained or lost will also determined by the exact charge of an atom. If an atom must lose 2 electrons to become stable, the ion will have a +2 charge.
Ionic bonding is the process of two ions bonding together through their negative and positive charges. Each ion a has a different charge, either positive or negative, and will bond to another ion with a similar charge. Only an ion with a positive charge can be bonded to an ion with a negative charge. Likewise, only ions with a negative charge will bond to an ion with a positive charge. Ions bonding ionically act as two magnets would. Unless one magnet has a positive charge and the other a negative, the two will repel each other; they must have opposite charges to bond. As well as being of opposite charges, the charge numbers must also be the same. As stated above, an ion is recognized as positive or negative, as well as by the number of electrons lost or gained. For two ions to bond ionically, the charges of these ions must be opposite each other, and the number of electrons lost or gained must be the same, or must be made the same through adding additional ions to the bond. For example, if ion 'A' has a +2 charge, and ion 'B' has a -3 charge, there must be 3 ions of 'A', and 2 ions of 'B' for these elements to bond ionically. Because the number of electrons lost or gained from each atom did not match each other, a common denominator was found to find the number of each atom needed to complete the charge of the other.
Covalent bonding is when two or more atoms share electrons to obtain the eight valence electrons needed to be in the most stable state and are bonded together through this act. Two atoms may bond and each have a certain number of electrons, however they still may need more electrons to attain the eight valence electrons needed to exist in their most stable state. By covalently bonding, these atoms are able to 'share' their electrons so a number of electrons can be used by both atoms, making both ions very stable. For example, two atoms of oxygen (oxygen has 6 valence electrons) may covalently bond together. They will each 'share' two of their electrons with the other atom; these electrons will stay in-between the two atoms and will be used by both atoms of oxygen. In this way, each oxygen atom will 'have' two more electrons, will have a full eight valence electrons, and will be in their most stable state possible.
A substance which is covalently bonded will have a low melting point, will conduct little to no electricity, and each particle of the substance will most likely not be in a lattice/crystalline shape. These substances are many times polymers. Ionically bonded substances have a high melting point, will conduct electricity when dissolved in liquid, and will be a lattice/crystalline shape. These substances are many times metals and ceramics. These properties help to determine whether a substance is ionically or covalently bonded.
Results:
Table 1: Properties of Covalently and Ionically Bonded Unkown Substances
Unknown Substances
Unknown A
Unknown B
Unknown C
Unknown D
Unknown E
Unkown F
Color
White clear
White clear
White
White clear
Yellow
White
Shape
Rectangular
Squared (soft Corners)
Random/ Jagged
Random/
Jagged
Round/
Jagged
Long crystals
Melting Point
Very low (15 Seconds)
Very high (Over 3 Minutes)
Medium/High (1:30 Minutes)
Medium (1:05 Minutes)
High (2:20 Minutes)
Low (20 Seconds)
Conductivity
Very Conductive
Very Conductive
Very Conductive
Very Conductive
Not Very Conductive
Very Conductive
Discussion:
The objective of this lab was to identify Unknown elements A, B, C, D, E, and F as covalently, or ionically bonded, using properties of each Unknown substance. Covalently bonded elements generally are known for having low conductivity, a low melting point, and not having a lattice, or symmetrical shape. Ionically bonded elements can be identified by having a very high melting point, being very conductive, and having a lattice shape.
The information in Table 1 (above), suggests that Unknown A is ionically bonded. This substance is very conductive, and has a rectangular, symmetrical shape. Although this element has a very low melting point, this substance has more characteristics of one which is ionically bonded. Unknown B is symmetrical in shape, has an exceptionally high melting point, and is very conductive. These properties suggest that Substance B is ionically bonded. Unknown C is random and jagged in shape, has a medium/high melting point, and is very conductive. These properties, and the fact that ionically bonded substances will be crystalline in shape, and will have a very high melting point suggest that Unknown C is covalently bonded. Based on the information gathered, Unknown substance D is covalently bonded. It is shaped random/jagged, has a medium melting point temperature, and is very conductive, this suggests that Unknown D is covalently bonded. Unknown E is shaped into round particles, has a high melting point, and has a low conductivity. These properties suggest that Unknown substance E is covalently bonded. Ionically bonded substances will have a lattice/crystalline shape, and will have a very high melting point, this unknown substance has neither of these, suggesting it is covalently bonded. Unknown substance F is shaped into long, symmetrical crystals, has a very low boiling point, and is very conductive. These properties suggest that Unknown F is ionically bonded. Although Unknown F has a low melting point, and is lattice shaped and has a high conductivity suggesting this compound is ionically bonded.
Many of the properties of the Unknown substances showed mixed properties of ionic and covalent bonding, suggesting some uncertainty in measurement in this lab. For example, a supposed characteristic of a covalently bonded substance is having a low boiling point, however, many of the substances which were identified as being covalently bonded also had a very high melting point. To improve certainty in measurement, a more controlled environment could have been used when testing for melting point. Different sized beakers, were used to melt the substances tested, and the flame used was not consistent. Both of which could have affected the results of the experiments. One could have melted the substance more quickly or slowly depending on what was used to melt the substance. To find an exact measurement of melting point, the same sized/thick beakers could have been used, as well as the same heat used to find an exact, and more accurate measurement of the melting point of each compound.
To find the exact shape of the particles of each substance, a more high powered microscope could have been used. Many of the substances were very small and hard to see exactly through the microscope used. An exact shape of each substance could have been easily observed by using a more powerful microscope. To better test for conductivity of each substance, a specific ratio of water to the Unknown substance being tested could have been used. This would have ensured that the conductivity measured would not have changed based on the concentration of the substance dissolved in the water. These improvements could have helped to solidify whether each Unknown substance is covalently or ionically bonded.
The objective of this lab was to test the properties of six separate unknown substances (A, B, C, D, E, and F). Then, using these properties, determine whether each Unknown substance is covalently or ionically bonded.
To become completely stable, an atom must have eight valence electrons. Valence electrons are the electrons found only on the outer ring (or subshell) of an atom. Once an atom has obtained all eight electrons, it will take a very large amount of energy to remove one of these from the atom, as the atom is in it's most secure state. Atoms which have less than eight valence electrons are less stable, and may lose electrons more easily depending on the number of electrons the atom is from obtaining all eight valence electrons.
Atoms which have three or less valence electrons will 'want' to lose these electrons so they may acquire the stable eight electrons on the next subshell closer to the nucleus of the atom. When these electrons are lost, the atom will become a positive ion. This happens because there are both protons and neutrons in the nucleus, (protons are positive and neutrons are neutral) this causes the nucleus of an atom to be positive, as the neutrons do not contribute to the charge of the atom as they have a neutral charge. Electrons have a negative charge, therefore, when these are taken away from an atom, it becomes a positive ion because there are less electrons present to counteract the positive charge of the nucleus. Atoms which have five or more electrons will 'want' to gain electrons so the outer shell will have a full eight valence electrons. When this happens, the atom will become negative as the electrons are cancelling out the positive charge of the nucleus. When an atom has four valence electrons, it may either gain or lose electrons to become more stable, based on if it is a metal or non-metal. If the element is a metal, the atom will lose electrons, if the element is a non-metal, it will gain electrons. The number of electrons gained or lost will also determined by the exact charge of an atom. If an atom must lose 2 electrons to become stable, the ion will have a +2 charge.
Ionic bonding is the process of two ions bonding together through their negative and positive charges. Each ion a has a different charge, either positive or negative, and will bond to another ion with a similar charge. Only an ion with a positive charge can be bonded to an ion with a negative charge. Likewise, only ions with a negative charge will bond to an ion with a positive charge. Ions bonding ionically act as two magnets would. Unless one magnet has a positive charge and the other a negative, the two will repel each other; they must have opposite charges to bond. As well as being of opposite charges, the charge numbers must also be the same. As stated above, an ion is recognized as positive or negative, as well as by the number of electrons lost or gained. For two ions to bond ionically, the charges of these ions must be opposite each other, and the number of electrons lost or gained must be the same, or must be made the same through adding additional ions to the bond. For example, if ion 'A' has a +2 charge, and ion 'B' has a -3 charge, there must be 3 ions of 'A', and 2 ions of 'B' for these elements to bond ionically. Because the number of electrons lost or gained from each atom did not match each other, a common denominator was found to find the number of each atom needed to complete the charge of the other.
Covalent bonding is when two or more atoms share electrons to obtain the eight valence electrons needed to be in the most stable state and are bonded together through this act. Two atoms may bond and each have a certain number of electrons, however they still may need more electrons to attain the eight valence electrons needed to exist in their most stable state. By covalently bonding, these atoms are able to 'share' their electrons so a number of electrons can be used by both atoms, making both ions very stable. For example, two atoms of oxygen (oxygen has 6 valence electrons) may covalently bond together. They will each 'share' two of their electrons with the other atom; these electrons will stay in-between the two atoms and will be used by both atoms of oxygen. In this way, each oxygen atom will 'have' two more electrons, will have a full eight valence electrons, and will be in their most stable state possible.
A substance which is covalently bonded will have a low melting point, will conduct little to no electricity, and each particle of the substance will most likely not be in a lattice/crystalline shape. These substances are many times polymers. Ionically bonded substances have a high melting point, will conduct electricity when dissolved in liquid, and will be a lattice/crystalline shape. These substances are many times metals and ceramics. These properties help to determine whether a substance is ionically or covalently bonded.
Results:
Table 1: Properties of Covalently and Ionically Bonded Unkown Substances
Unknown Substances
Unknown A
Unknown B
Unknown C
Unknown D
Unknown E
Unkown F
Color
White clear
White clear
White
White clear
Yellow
White
Shape
Rectangular
Squared (soft Corners)
Random/ Jagged
Random/
Jagged
Round/
Jagged
Long crystals
Melting Point
Very low (15 Seconds)
Very high (Over 3 Minutes)
Medium/High (1:30 Minutes)
Medium (1:05 Minutes)
High (2:20 Minutes)
Low (20 Seconds)
Conductivity
Very Conductive
Very Conductive
Very Conductive
Very Conductive
Not Very Conductive
Very Conductive
Discussion:
The objective of this lab was to identify Unknown elements A, B, C, D, E, and F as covalently, or ionically bonded, using properties of each Unknown substance. Covalently bonded elements generally are known for having low conductivity, a low melting point, and not having a lattice, or symmetrical shape. Ionically bonded elements can be identified by having a very high melting point, being very conductive, and having a lattice shape.
The information in Table 1 (above), suggests that Unknown A is ionically bonded. This substance is very conductive, and has a rectangular, symmetrical shape. Although this element has a very low melting point, this substance has more characteristics of one which is ionically bonded. Unknown B is symmetrical in shape, has an exceptionally high melting point, and is very conductive. These properties suggest that Substance B is ionically bonded. Unknown C is random and jagged in shape, has a medium/high melting point, and is very conductive. These properties, and the fact that ionically bonded substances will be crystalline in shape, and will have a very high melting point suggest that Unknown C is covalently bonded. Based on the information gathered, Unknown substance D is covalently bonded. It is shaped random/jagged, has a medium melting point temperature, and is very conductive, this suggests that Unknown D is covalently bonded. Unknown E is shaped into round particles, has a high melting point, and has a low conductivity. These properties suggest that Unknown substance E is covalently bonded. Ionically bonded substances will have a lattice/crystalline shape, and will have a very high melting point, this unknown substance has neither of these, suggesting it is covalently bonded. Unknown substance F is shaped into long, symmetrical crystals, has a very low boiling point, and is very conductive. These properties suggest that Unknown F is ionically bonded. Although Unknown F has a low melting point, and is lattice shaped and has a high conductivity suggesting this compound is ionically bonded.
Many of the properties of the Unknown substances showed mixed properties of ionic and covalent bonding, suggesting some uncertainty in measurement in this lab. For example, a supposed characteristic of a covalently bonded substance is having a low boiling point, however, many of the substances which were identified as being covalently bonded also had a very high melting point. To improve certainty in measurement, a more controlled environment could have been used when testing for melting point. Different sized beakers, were used to melt the substances tested, and the flame used was not consistent. Both of which could have affected the results of the experiments. One could have melted the substance more quickly or slowly depending on what was used to melt the substance. To find an exact measurement of melting point, the same sized/thick beakers could have been used, as well as the same heat used to find an exact, and more accurate measurement of the melting point of each compound.
To find the exact shape of the particles of each substance, a more high powered microscope could have been used. Many of the substances were very small and hard to see exactly through the microscope used. An exact shape of each substance could have been easily observed by using a more powerful microscope. To better test for conductivity of each substance, a specific ratio of water to the Unknown substance being tested could have been used. This would have ensured that the conductivity measured would not have changed based on the concentration of the substance dissolved in the water. These improvements could have helped to solidify whether each Unknown substance is covalently or ionically bonded.