Hello!
Find the Energy of the Photon by Planck's Equation, given:
E (photon energy) =? (in Joule)
h (Planck's constant) = 
f (radiation frequency) =
Therefore, we have:





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Answer:
Metal
Element: Calcium
Valency: 2
Explanation:
To find the element, let's use the periodic table. (Look below)
We already went past 3 shells, just need the 2 electrons after it.
Just skip to the 4th row and count 2 to the right
We end up at Calcium.
Calcium is a metal and we're also on the alkaline earth metals column.
Calcium will need to lose 2 electrons to reach stability, so the valency is 2.
Answer:
Explanation:
2 Na+ 2 H2O → 2 NaOH + 1 H2
Answer:
The number before any molecular formula applies to the entire formula. So here you have five molecules of water with two hydrogen atoms and one oxygen atom per molecule. Thus you have ten hydrogen atoms and five oxygen atoms in total.