Questions tagged [periodic-trends]
Trends which are observed in the properties of elements as you move along the periodic table in a given direction.
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Why does chlorine have a higher electron affinity value than fluorine? [duplicate]
Why does chlorine have a higher electron affinity value than fluorine? Since this periodic property tends from the bottom up (in the group), the logic would be that the fluorine is the element with ...
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Atomic radius decreasing across a Periodic Table row - does the RPD of an orbital change depending of the element considered?
I have a concern regarding the RPD of an orbital. Does the RPD of an orbital depend on the $Z$ (i.e. on the element under consideration) ? Especially, can the RPD of an orbital "shrink" to ...
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Why is the covalent radii of carbon significantly smaller than that of boron, and why do metals have more significant changes in radii
I’m currently looking at this graph of the 2nd-period covalent radii, and it seems like moving from boron to carbon, there is a more significant decrease compared to moving across the rest of the ...
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Why does the 1st ionisation energy decrease from the 9th period to the 10th period
I’m currently looking at the ionisation energy chart within my chemistry textbook and while I know that there are not really meaningful periodic trends within transition metals, generally the ...
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Are Fajans rules relevant to melting and boiling points of alkali metal hydrides?
Among LiH, NaH, KH, RbH, CsH the one with the highest melting point is LiH, and it keeps on decreasing till CsH. The reason for this in my textbook is that the size of cations keeps on increasing down ...
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I was told that Lithium and group 2 bicarbonates does not decompose on heating.Group 1 bicarbonates does decompose except lithium
But in some sources it was explained that stability of group 1 bicarbonates increases down the group.If it is true then how does lithium bicarbonate does not decompose ?.Can anyone please tell me ...
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Upon what does the half life of a nuclide depend on? [duplicate]
Nuclide half-lives seem to be apparently random, except for the fact that heavier elements are typically radioactive and lighter ones stable. Is there any factor that can predict the half life of a ...
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Why aren't other elements with valence 6s electrons liquid like mercury?
I found out that mercury's 6s electrons undergo relativistic effects that make their pull to the nucleus greater, which makes it so that they can't bond with other atoms of mercury to form a solid. ...
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Why is there anomalous trend in third ionization energy for Pr-Pm and Dy-Er?
It is not hard to observe the anomalously flat regions at Pr-Pm and Dy-Er in the trend of IE3 of lanthanides:, each described as the "first quarter" and "third quarter". Why is ...
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Can the relative reactivity of metals be explained by ionization energy and/or electronegativity?
I'm a 9th grade physical science teacher, and we're currently learning periodic trends. This is the first chemistry my students have learned. One of our labs for this unit has to do with the relative ...
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How would you explain the general trend in melting point between Group 1 and Group 2 chlorides?
This question is based off of the attached chart. I notice how there's a general increase in melting point down group 2 chlorides and a general decrease (except for Lithium) down the group 1 chlorides....
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Ionic radii of cations and anions
My textbook mentions that across a period from left to right, the ionic radius of atoms decreases. I'm a bit puzzled because negative ions in the same period have an extra shell. I get the part about ...
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Does Cu+ have a greater ionic radius than Sr2+?
Although Strontium is in group 2, reducing the number of electrons as it becomes ionized makes it group 18, period 4 in terms of electrons. Therefore, ionized Strontium (Sr2+) is in the same period as ...
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Why aren't lanthanum, praseodymium, osmium, and mercury not on the same energy level?
The following question is from "The Official Guide to the HiSET Exam, Second Edition 2nd Edition", published by McGraw Hill, 2nd edition (March 25, 2016).2016 text, p. 75 (ISBN10: 1259640795)...
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Queries regarding Lanthanoid Contraction
Consider these two statements regarding lanthanoid contraction and their explanation as understood by me.
Lanthanoid contraction is the greater than expected decrease in the atomic radii of the ...
