Answer:
D. 0.75 grams
Explanation:
The data given on the iridium 182 are;
The half life of the iridium 182,
= 15 years
The mass of the sample of iridium, N₀ = 3 grams
The amount left, N(t) after two half lives is given as follows;

For two half lives, t = 2 × 
∴ t = 2 × 15 = 30


∴ The amount left, N(t) = 0.75 grams
The objects which cannot be observed in detail without a microscope
include the following:
<h3>What is a Microscope?</h3>
A microscope is an instrument which is used to view smaller objects such as
microbe,cells, tissues etc. This instrument is used in viewing the different
cells found in the body as they can't be seen with the eye.
The remaining options which can be seen with the eyes don't require
the use of microscopes.
Read more about Microscope here brainly.com/question/25268499
Orbital shell notation of fluorine is 2. 7 while that of oxygen s 2. 6. This means that these elements (that follow each other in the periodic table) will have high electronegativity in molecules due to their high atomic number (which causes them to strongly attract electron orbital shell closer to their nucleus). NB: Atomic number of a peroid increased from left to right of the periodic table.
Therefore, in the first molecule, the negative dipole would most likely be located between the F atoms In the second molecule the negative molecule would be most likely located in the between the O and F atoms.
Elements that exceed the octet rule must have an unoccupied d orbital. I believe.