Answer:
C.) Argon
Explanation:
This is because ionisation energy increases as we move from left to right in a period. Argon presents in the right most column and Argon is a novel gas and has 8 electrons in outermost orbital. So, it is highly stable. I hope I helped! ^-^
Scale and measuring tape.
To determine the mass and volume, you can find the density. The block will float if its density is less than that of water.
Answer:
1.07 g Ba
Explanation:
Hello there!
In this case, according to the definition of the Avogadro's number and the molar mass, it is possible to say that 6.022x10^{23} atoms of barium equal one mole, and at the same time, 1 mole equals 137.327 grams of this element; thus, it is possible to say that 6.022x10^{23} atoms of barium have a mass of 137.327 grams; therefore, it i possible for us to calculate the required mass in grams as shown below:

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So, what's your question..?. You just gave options..
I believe the answer is C, AgBr. I hope this helps