7. Atomic mass
8. Atomic number
9. Chemical symbol
10. Right
Answer: The rate constant is
Explanation ;
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = ?
t = age of sample = 4.26 min
a = initial amount of the reactant = 2.56 mg
a - x = amount left after decay process = 2.50 mg
Now put all the given values in above equation to calculate the rate constant ,we get



Thus rate constant is [tex]0.334s^{-1}
Rutherford, Geiger and Marsden's experiment proved that every atom has a nucleus and that this nucleus is of positive charge and contains the most of the mass of the atom. 0.005% of the volume occupied by the electrons is the volume of the nucleus.
<u>Answer:</u> The correct answer is Option 5.
<u>Explanation:</u>
- To calculate the molarity of the solution after mixing 2 solutions, we use the equation:

where,
are the n-factor, molarity and volume of the NaOH.
are the n-factor, molarity and volume of the 
We are given:
Putting all the values in above equation, we get:

- To calculate the molarity of acid, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base.
We are given:

Putting values in above equation, we get:

Hence, the correct answer is Option 5.
Answer:
Neutral or uncharged
Explanation:
The positive charge on a proton is equal in magnitude to the negative charge on an electron. As a result, a neutral atom must have an equal number of protons and electrons.