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Course: AP®︎/College Chemistry > Unit 2
Lesson 1: Types of chemical bondsPredicting bond type (metals vs. nonmetals)
One way to predict the type of bond that forms between two elements is to consider whether each element is a metal or nonmetal. In general, covalent bonds form between nonmetals, ionic bonds form between metals and nonmetals, and metallic bonds form between metals. Created by Sal Khan.
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is Ununoctium (118) a metal or nonmetal, a noble gasses or not?(4 votes)
Firstly, element 118 is no longer named ununoctium and has not been named so since 2016. Ununoctium was a placeholder name for element 118 giving by the IUPAC in 1979 which was intended to be used until its discovery was confirmed since the people who discover an element gain the right to name it. In 2016 is was officially decided to name it Oganesson (which the chemical symbol of Og) after Russian physicist Yuri Oganessian whose team helped synthesize superheavy elements 107 through 118. It was given the "-on" suffix since it belongs to group 18 along with the noble gases who all have suffixes of "-on".
So since so few atoms of Og have been created it's hard to say conclusively what it's properties are as of now. It's in the same group as the noble gases (which are nonmetals), but has been hinted that it may be solid under normal conditions and significantly reactive. Which would be a break from the trend of the group of unreactive gases at normal conditions. So it's unclear as of now what it is.
Hope that helps.(12 votes)
if non metals are bad conductor of electricity the why graphite( an allotrophe of carbon) is a good conductor electricity??(3 votes)
Yes, most Non-metals are bad conductors of electricity but there is an exception for Graphite because of its structure.
Its structure - https://tirupatigraphite.co.uk/images/molecular-structure-flake-graphite.png
If you notice, you will see that every Carbon atom is covalently bonded with others, using Only 3 of its valence electrons, while another electron remains free. Because of such free electrons of all the Carbon atoms in that allotrope, electricity flows easily through it using those delocalized (free) electrons.
Even though generally, non-metals are bad conductors and metals are good, there always exist exceptions in nature. And we learn that with time and research :)
Ask if anything is unclear.(12 votes)
- Why can’t oxygen and hydrogen form an ionic bond with oxygen stealing two electrons from the hydrogens, making it two hydrogens with a plus 1 charge and one oxygen with a -2 charge? I know how they can form a covalent bond but why can’t they also form an ionic bond? If it’d rather form a covalent bond, could you “force” it to make an ionic bond but adding some energy or something?(2 votes)
- For an ionic bond to happen, the electronegativity difference between the two bonding atoms has to be large enough. A large electronegativity difference means that a very electronegative atom was bonded with a not so electronegative atom. The very electronegative atom in an ionic bond will attract electrons to itself to such a degree that it removes electrons from the other, less electronegative atom.
Using the Pauling scale of electronegativity we need a difference greater than 2.0, x > 2.0. Hydrogen's electronegativity value is 2.20 while oxygen is 3.44, which result in a difference of 1.24 (3.44 - 2.20 = 1.24). This would place the hydrogen oxygen bond in the polar covalent range instead of the ionic range. So hydrogen and oxygen do not form an ionic bond simply because they do not have a large enough electronegativity difference. We can't do anything to change the polar covalent bond into an ionic bond because it's the identity of the elements which is determining the type of bond.
Hope that helps.(7 votes)
What makes the noble gases "noble"?(2 votes)
They dont react with other elements as the valence electron shell is complete. idk why they are called noble though. just a naming scheme(4 votes)
- What makes the noble gases "noble"?(2 votes)
- Noble here being a synonym for unreactivity. Using noble in this sense was first applied to certain transition metals, called the noble metals, due to their low reactivity. When the group 18 elements were discovered, they were found to be very unreactive, similarly to the noble metals. So the group 18 elements become known as the noble gases since they were unreactive naturally found as gases.
Hope that helps.(3 votes)
- is there any kind of limitation in ionic bond formation?(2 votes)
apparently metalloids (like Germanium) act unusually in chemical bonds, How so? how would Ge bond with F (nonmetal) and how would it bond with sodium (metal) if they could bond?(2 votes)- if non metals are bad conductor of electricity the why graphite( an allotrophe of carbon) is a good conductor electricity?(1 vote)
- So we need to know why metals are generally conductive to understand that. Electricity is the directed movement of electrons under influence from a voltage source. So to be a conductor, an atom has to have easily removable electrons which can be transferred between neighboring atoms. Metals (particularly the transition metals) are generally good at this because they generally have low ionization energies which allow for easy electron removal. They simply don’t have a very strong hold of their valence electrons. But not all metals are equally good conductors, there are differences among the metals. Silver is about 6 times more conductive than iron is for example. And again, it just comes down to how easily we can transfer electrons between the atoms.
Carbon is interesting because it exists as different allotropes which different degrees of conductivity. Graphite being a good conductor. Once again, it comes to how easily removable the electrons are from the atoms. Here we need to know the structure of graphite.
Graphite is a lattice composed of sheets of carbon atoms bonded in repeating hexagonal units (individual sheets being called graphene). Graphite is composed of many layers of these graphene sheets. Within a single sheet, the carbon atoms bond to each other using pi bonds which are more delocalized and allow easy removal of electrons from one carbon and addition to a neighboring. However, between the sheets, there only exists weaker Van der Waals forces where electrons cannot easily migrate between. So graphite is conductive within the individual sheets, but not between them.
Hope that helps.(1 vote)
Video transcript
- [Instructor] In a previous video, we introduced ourselves to the
idea of bonds between atoms, and we talked about the types of bonds, ionic, covalent and metallic. In this video we're going
to dig a little bit deeper and talk about the types of bonds that are likely to be formed
between different elements. And to understand that,
I'm going to introduce a broad classification of the elements, and in general, we're just
going to think about things as metals and as nonmetals. So before I even point out on
the periodic table of elements what are the metals and
what are the nonmetals and maybe what are the
ones that are in between, what are the properties of metals? Well, generally speaking,
they conduct electricity. Conduct electricity. They tend to be malleable,
which is just a fancy way of saying that you can
bend them without breaking. And generally speaking, and
there's exceptions to this, they are solid at room temperature. So I'll say solid at room temperature. Now what do you think the properties of nonmetals are going to be? Well generally speaking, they're going to be the opposite of this. Nonmetals, generally speaking, at room temperature are often not solid, they're often times gasses. They are not going to
conduct electricity well. Now when you look at a
periodic table of elements, how do you divide the
metals from the nonmetals? Well that's what this
little scratchy yellow line I'm drawing is trying to indicate. So everything above and to
the right of this yellow line is a nonmetal and if you
look at the color code from the folks who made this
periodic table of elements, everything in this yellow
color that we have here, so hydrogen and carbon and nitrogen and oxygen and fluorine,
chlorine, I could keep going, these are all nonmetals. And it is the case that generally speaking at room temperature, they
will be in a gas form and they will not
conduct electricity well. These things in blue we've
talked about in other videos, these are the noble gasses. So these are also nonmetals. The people who made this
periodic table of elements put them in their own color 'cause then you could view
them as a subclass of nonmetals and they tend to be very inert, they don't interact with other things. They don't tend to form
any of these bonds. Now everything else, you can consider in some form to be a metal and the reason why this
periodic table of elements has different colors is that
there's subclassifications of the metals but generally speaking,
all of these things that you see right over here below this scratchy yellow line have the properties, generally speaking, of conducting electricity,
being malleable, being solid at room temperature. And these things that straddle this yellow line right over here, these things that are in this kind of bluish-green kind of color, these are sometimes viewed as metalloids because they have some
properties of metals and some properties of nonmetals. But generally speaking,
if you know whether the things reacting are
metals or nonmetals, you can oftentimes
predict what type of bond is going to form. So for example, if I have
a bond between a metal, a metal and a nonmetal, and a nonmetal, what type of bond do you
think is going to form? Well when you bond between a net metal and a nonmetal, and we
saw an example of that in that first video on bonding, say a metal like sodium, and
then a nonmetal like chlorine, we saw that that chlorine
will swipe an electron, the sodium might lose one, then the chlorine atom
becomes a chloride anion, and then the sodium atom
becomes a sodium cation and then they become
attracted to each other and then you form an ionic bond. So this tends to form ionic bonds. Now what if you were to have
a nonmetal with a nonmetal? Nonmetal times two, so two nonmetals bind, bound, I'm having trouble saying it, two nonmetals bonding to each other. What do you think is going to happen? Well we saw as an example
in that first video where we say well what happens
if oxygen bonds to oxygen? Well we saw that was a covalent bond and that is generally the case when you have two nonmetals
form bonds, it is covalent. And then last but not least, and this might be the most
obvious one of them all, what do you think happens when you have two metals forming a bond? Well you can imagine that
will be a metallic bond where they contribute
electrons to this kind of sea of electrons and
that's what makes them conduct electricity so well and malleable. So I'll leave you there. There are exceptions to
everything I just talked about but generally speaking, these notions will serve you well, especially in an
introductory chemistry class.