<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.
D is to stop the current and the force can be removed
Answer:
1. it is symbolized as 4/2 He
: Alpha rays
2. it has the weakest penetrating power
: Alpha rays
3. It is a high-speed electron
: beta rays
4. It possesses neither mass nor charge
: gamma rays
5. it has the strongest penetrating power
: beta rays
6. its is symbolized as 0/-1e
: beta rays
7. it is the most massive of all the components: alpha rays
Explanation:
Let us consider the characteristics of each of the given rays.
α rays: These are helium nucleus so are symbolized by 
Due to two protons and two neutrons unlike beta and gamma rays these are the most massive and thus have least penetrating power among the three given rays.
β rays: These are actually high speed electrons and are symbolized as 
. Due to lesser mass than alpha rays they are more penetrating than them however less penetrating than gamma rays.
γ rays : They carry no charge or mass. Due to least massive among the three rays they have highest penetrating power.
In a endothermic reaction energy from an outside source is continuously being added.
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