Lets take the Lanthanides as an example. Lanthanum has its 5d sublevel filled before its 4f, even though the 4f is lower in energy and should, by the Aufbau Principle, be filled first. However, this is an exception because it happens to be the most stable configuration. It has one electron in the 5d sublevel and none in the 4f, and since it has no "f" electrons, it cannot be part of the f-bar's upper row (the Lanthanide series).
The Lanthanides themselves will each also have one electron in the 5d sublevel, and the first element will also have one in the 4f sublevel. This trend will continue for all 14, and thus the 4f sublevel is filled. Hafnium, the element immediately after the last Lanthanide, will resume filling the 5d sublevel as normal, with two electrons in it and a completely filled 4f sublevel. The anomaly does not really change much; after all, if the valence electron in Lanthanum were not in the 5d sublevel and instead in the 4f, it would start off the Lanthanide series, there would be 14, and it would simply end one element before it normally does. The numbers all add up, in any case, and this is the natural order of things.
For Actinides, replace the word Lanthanum with Actinium, Hafnium with Darmstadtium, 5d with 6d, and 4f with 5f. Everything works out perfectly; all the confusion is just caused by the stubborn little electron who doesn't want to be the first f-block element (and so he moves up into 5d, and stays there while the others take their appropiate places, which are moved one up thanks to his desire to maintain stability).
From the earlier known chemical properties of Actinium (89) up to Uranium (92), indicating a relation to the transition metals, it was generally assumed that the transuraniums would have similar qualities. During his Manhattan Project research in 1944, Glenn T. Seaborg experienced unexpected difficulty isolating Americium (95) and Curium (96). He began wondering if these elements more properly belonged to a different series than the transition metals, which would explain why the expected chemical properties of the new elements were different. In 1945, he went against the advice of colleagues and proposed the most significant change to Mendeleev's periodic table to have been accepted universally by the scientific community: the actinide series.
how god explain buried fossil
It helps explain metallic bonds.
The abstract noun forms for the verb 'to explain' are explanation and the gerund, explaining.
The abstract noun forms for the verb 'to explain' are explanation and the gerund, explaining.
From the earlier known chemical properties of Actinium (89) up to Uranium (92), indicating a relation to the transition metals, it was generally assumed that the transuraniums would have similar qualities. During his Manhattan Project research in 1944, Glenn T. Seaborg experienced unexpected difficulty isolating Americium (95) and Curium (96). He began wondering if these elements more properly belonged to a different series than the transition metals, which would explain why the expected chemical properties of the new elements were different. In 1945, he went against the advice of colleagues and proposed the most significant change to Mendeleev's periodic table to have been accepted universally by the scientific community: the actinide series.
227Ac----- alpha decay---- 223Fr
Probable lanthanum.The chemical reactivity (and electronegativity) are very similar for lanthanoids. This explain the difficulties of identification and separation.
"Explain this" is actually "You explain this" or some form of that phrase. As such, "You" is the [understood] subject and "explain" is action requested, i.e. the verb. Or another way of saying it is "explain" IS the verb, "explanation" is the noun, as in "You please explain the written explanation to me.' or simply "Explain it to me Lucy".
Explain RAM? Explain RAM?
explain
i think it depends on WHERE you explain it and WHO you explain it to.
Explain is present tense. I/We/You/They explain He/She/It explains The present participle is explaining.
What does "explain" mean? To "explain" something is to tell in detail what something means.
Topic Sentence * 1st Supporting detail/reason/fact * Explain * Explain * 2nd Supporting detail/reason/fact * Explain * Explain * 3rd Supporting detail/reason/fact * Explain * Explain Conclusion
No, the word "explain" is not present tense. "Explain" is the base form of the verb, and it can be used in various tenses like present ("I explain"), past ("I explained"), or future ("I will explain").
Give me a chance to explain what happened.If you're confused, I'll explain the directions again.When he took the stand, the defendant tried to explain the reason for his actions.