Which of these elements is a noble gas? hydrogen (H) barium (Ba) nitrogen (N) krypton (Kr) bromine (Br)
2 answers:
Answer : The correct option is krypton (Kr).
Explanation :
Noble gas : It is a group which is present at last in the periodic table and they belongs to group 18.
The general electronic configuration of noble gas is .
The noble gas contains six elements which are helium, neon, argon, krypton, xenon and radon.
According to the question,
- Hydrogen belongs to group 1 which is a alkali metal.
The general electronic configuration of hydrogen is .
- Barium belongs to group 2 which is an alkaline earth metal.
The general electronic configuration of barium is .
- Nitrogen belongs to group 15 which is a non-metal.
The general electronic configuration of nitrogen is .
- Bromine belongs to group 17 which is a halogen.
The general electronic configuration of bromine is .
- Krypton belongs to group 18 which is a noble gas.
The general electronic configuration of krypton is .
Therefore, the correct answer is krypton (Kr).
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Answer:
The amount of sodium is 32 mg per cracker, 49 mg per pretzel and 68 mg per cookie.
Explanation:
Let's assume amount of sodium is x mg per cracker, y mg per pretzel and z mg per cookie.
So, the following three equations can be written as per given information:
x+y+z = 149 ........(1)
8y+8z = 936 ........(2)
6x+7y = 535 .........(3)
From equation- (2), y+z = = 117
By substituting the value of (y+z) in equation- (1) we get,
x = 149-(y+z) = 149-117 = 32
By substituting the value of x into equation- (3) we get,
y = = 49
By substituting the value of y into equation- (2) we get,
z = (117-49) = 68
So, the amount of sodium is 32 mg per cracker, 49 mg per pretzel and 68 mg per cookie.