Answer:
₁₁A
Explanation:
Atomic radius
As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons.
This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases.
So in given elements consider A₁₁, B₁₂, C₁₃ ans D₁₇ as sodium, magnesium, aluminium and chlorine. This is the third period and as we move form sodium to chlorine atomic radius decreases. That's why sodium has greater size.
As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased
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Answer:
the reactivity of alkaline earth metals increases from top to the bottom of the group, that's because the atoms get bigger from the top to the bottom so the valence electrons are farther from the nucleus.
A . A person Jumping represents an unbalanced force.
<u>Explanation:</u>
If equal amount of force applied on any object from both the directions, then the object will not move and so the force is a balanced force.
If an unequal amount of force on an object from both sides then the object will move in the opposite direction of the maximum force applied, so it is called as an unbalanced force.
- When the force is unbalanced then its velocity will change, so options C and D are omitted.
- In Option B the vase is sitting on a table, just kept so there is no action of any unbalanced force.
- But a person jumping represents an unbalanced force, since the person do not jump with constant velocity and it will vary.
