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!
The 'dark side' of the Moon refers to the hemisphere of the Moon that is facing away from the Earth. ... It is only 'dark' to us, as that hemisphere can never be viewed from Earth due to a phenomenon known as 'Tidal Locking'
Answer:
0.5kg
Explanation:
Given parameters:
Speed of the object = 12m/s
Kinetic energy = 36J
Unknown:
Mass of the object = ?
Solution:
Kinetic energy is the energy due to the motion of a body. It is mathematically expressed as;
K.E = 
m v²
Insert the parameters and solve;
36 = x m x 12²
36 = 72m
m = 0.5kg
Answer:
The correct option is B.
Explanation:
Ionic bond are usually formed between a metal and a non metal. The metal usually acts as the electron donor while the non metal acts as the electron acceptor, that is, the metal give away electrons while the non metal accept the electrons. In the options given in this question, it is only the pairs in option B, that is qualify for ionic bond, this is because it consist of a metal and a non metal.
