Answer:
3
Explanation:
Atomic number refers to the number of protons in the nucleus of the atom.
and since there are 3 protons, the atomic number is 3
 
        
                    
             
        
        
        
The answer for the following problem is mentioned below.
- <u><em>Therefore the final volume of the gas is 52.7 ml.</em></u>
Explanation:
Given:
Initial pressure ( ) = 290 kPa
) = 290 kPa
Final pressure ( ) = 104 kPa
) = 104 kPa
Initial volume ( ) = 18.9 ml
) = 18.9 ml
To find:
Final volume ( )
)
We know;
From the ideal gas equation;
     P × V = n × R × T
where;
P represents the pressure of the gas
V represents the volume of gas 
n represents the no of the moles
R represents the universal gas constant 
T represents the temperature of the gas
So;
    P × V = constant 
    P ∝ 
From the above equation;
               
 represents the initial pressure of the gas
 represents the initial pressure of the gas 
 represents the final pressure of the gas
 represents the final pressure of the gas
 represents the initial volume of the gas
 represents the initial volume of the gas 
 represents the final volume of the gas
 represents the final volume of the gas
Substituting the values of the above equation;
                      =
 = 
               = 52.7 ml
 = 52.7 ml
<u><em>Therefore the final volume of the gas is 52.7 ml.</em></u>
 
        
             
        
        
        
Answer:
Option B. Malleable, Conductor, High melting point, Lustrous
Explanation:
Mg has a higher melting point because of the strong electrostatic force of attraction between the magnesium ions (Mg^2+). The rest properties listed are all general properties of metals 
 
        
             
        
        
        
Answer:
D
Explanation:
D is not necessary to follow lab safety in Laboratory 
 
        
             
        
        
        
Metallic bonds<span>, the valence electrons from the s and p orbitals of the interacting metal atoms delocalize</span>