Answer:

Explanation:
The formula of density is:

If the formula is rearranged for volume, it becomes:

The mass of the platinum is 38.5 grams.
The density is 21.5 grams per cubic centimeter.

Substitute the values into the formula.

Divide. Note that the grams (g) will cancel each other out.

Round to 2 decimal places (hundredth place). The 0 in the thousandth place tells us to leave the 9 in the hundredth place.

The volume is about <u>1.79 cubic centimeters.</u>
Se - 78
Selenium - 78
or
78/34 Se2-
> How many valence electrons does a helium atom have?
The electron configuration of Helium is simply 1s2. We see
that its outermost shell is the s shell and it contains 2 electrons, therefore
the number of valence electrons is also 2.
> What is the formula of the ion formed when potassium
achieves noble-gas electron configuration?
Potassium has a electron configuration of [Ar] 4s1. To
have an electron configuration of only [Ar] which is a noble gas, the one electron
from 4s1 should be removed, hence:
<span>K+</span>
Answer:
I think it's b if not then sorry
In nature, water exists in the liquid, solid, and gaseous states. It is in dynamic equilibrium between the liquid and gas states at 0 degrees Celsius and 1 atm of pressure. At room temperature (approximately 25 degrees Celsius), it is a tasteless, odorless, and colorless liquid.