Wanted to write more both there is a problem with the editor. Uranium is formed naturally in the crust of rocks and seawater. Plutonium does not occur in nature. It is found in the biosphere.
<span>The correct answer is weakened economic strength. When a declning population size starts to occur and develop, the country may experience a weakened economic strength, since the power to produce and create products and services has been hindered and weakened due to its declining population.</span>
Answer:
Below are the statements which are true about the structure of the periodic table:
B: The inner transition elements are placed at the bottom of the periodic table for easy viewing.
D: The distribution of electrons in energy levels is responsible for the shape of the periodic table.
Explanation:
Point A:
As we know that in a periodic table there are 7 period s and 18 groups. So, the number of periods is evidently lesser than the number of groups. But the shape of periodic table is regular and rectangular so point A is false.
Point B:
The inner transition elements or -f block elements are put at the bottom for easy viewing. These are the elements that have the valence electrons only in the f-orbital's. Therefore, they are placed separately at the bottom side of the table so that they can be easily viewed or studied from there. So, point B is true.
Point C:
If we talk about option C, then it is very clear and true that considering a rectangular shape of the periodic table, the groups are vertically arranged and periods are horizontally arranged, therefore it is false.
Point D:
Atoms of all elements have definite electronic distribution in different energy levels like s, p d or f. This is a very prominent feature of periodic tale that elements are divided in specific blocks, s, p, d and f based on their electronic configurations. Therefore, it is true.
Point E:
We also know that no. of metals in a periodic table are more than the no. of non metals like almost 91 out of 118 elements are metals in periodic table. Therefore, the point E "Nonmetals take up more than half the area of the periodic table." is false.
Hope it helps!
Answer:
Igneous Rocks: form by crystallizing melted material (magma).
Explanation:
They can form either on the surface (extrusive igneous rocks), or deep in the crust (intrusive or plutonic igneous rocks).
Since the sun is the main source of evaporation on earth's surface, then the answer should be Solar since solar refers to the sun. It's usually not visible though because it mostly occurs over oceans where it is not seen from the shores.
