# of protons + # of neutrons = mass
9 + 10 = 19
the answer is D
your answer would be a. usually liquid or gas at room temperature
Based on the Hund's Rule, the three electrons in a 2p orbital are arranged as shown in option C.
<h3>What is an orbital?</h3>
The term orbital refers to a region in space where there is a high probability of finding the electron. We know that an electron in an atom could be defined by the use of four sets of quantum numbers which are;
- The principal quantum number
- The orbital quantum number
- The spin quantum number
- The magnetic quantum number
Hund's rule states that, electrons occur singly before pairing takes place. In this case, we can see that the only arrangement that obeys the Hund's Rule is option C.
Learn more about Hund's rule:brainly.com/question/12646067
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Answer:
Explanation:
Given :
Mass of a bar of lead = 115.2 g
Initial water level 
= 25 mL
Final water level = 35.5 mL
Difference in the water level = 35.5 - 25
= 10.5 mL
= 
We know that when a body is submerged in water, it displaces its own volume of water.
Therefore, the volume of the lead bar = volume of the water displaced = 10.5 mL =
We know that mathematically, density is the ratio of mass of body to its volume.
Density of the lead bar is given by :
=
<span>Charles law states that volume of a gas is directly proportional to temperature at constant pressure for a fixed amount of gas. the pressure at given conditions is 1.00 atm and the standard pressure at STP conditions too is 1.00 atm therefore pressure remains constant.
V1/T1 = V2/T2
the parameters for the first instance are on the left side and parameters at STP are on the right side of the equation.
T1 - temperature in kelvin - 273 + 30.0 </span>°C <span>= 303 K
T2 - standard temperature - 273 K
V1 - volume - 50.0 L
substituting the values in the equation
50.0 L / 303 K = V / 273 K V = 45.0 L
answer is 2) 45.0 L </span>
