<u>Answer: </u>The correct statement is X is the effective nuclear charge, and it increases across a period.
<u>Explanation:</u>
We are given that:
X = number of protons − number of core electrons
Effective nuclear charge is defined as the actual nuclear charge (Z = number of protons) minus the screening effect caused by the electrons present between nucleus and valence electrons. These electrons are the core electrons.
The formula used for the calculation of effective nuclear charge given by Slater is:

where,
= effective nuclear charge
Z = atomic number or actual nuclear charge or number of protons
= Screening constant
The effective nuclear charge increases as we go from left to right in a period because nuclear charge increases with no effective increase in screening constant.
Hence, the correct answer is X is the effective nuclear charge, and it increases across a period.
Answer: B- Chemical bonds are formed. Energy is released in the form of heat.
Explanation: I hoped that helped !
Answer:
Neither arre correct
Explanation:
Neither Anya nor Braden are correct. This is because if you use 90 degrees, 180 degrees, or even 270 degrees you will not get the exact image, which means that the image will not be found by just a rotation because there will be a curve in the image. You can solve it if you can do 90 degree rotation and translation.
Answer:
Metal
Explanation:
Lithium (Li), chemical element of Group 1 (Ia) in the periodic table, the alkali metal group, lightest of the solid elements. The metal itself—which is soft, white, and lustrous—and several of its alloys and compounds are produced on an industrial scale.
Atomic number: 3
Atomic weight: 6.941
Rainwater can have a ph as low as 3, meaning that it is very C. Acidic