Answer:
<h3>I don't know what is the answer of your question sorry never mind..</h3>
Explanation:
<h3>And please marks me as brainliest... </h3>
The number of half -lives that has passed after 105 hours for krypton-79 that has half-life of 35 hours is calculated as below
if 1 half life = 35 hours
what about 105 hours = ? half-lives
= (1 half life x105 hours) /35 hours = 3 half-lives has passed after 105 hours
Answer:
The first energy level is closest to the nucleus. The second energy level is a little farther away than the first. ... The electrons in the energy level farthest from the nucleus are called valence electrons. Atoms in the same column (group) in the periodic table have the same number of valence electrons.
Explanation:
Answer:
A. The object broke apart and seemed to disappear when dropped into the glass of water.
Explanation:
In a physical change, the physical properties of the matter usually the state of the matter is altered. Most physical changes are usually reversible and does not lead to the production of new substances.
When the solid object was dropped into the water beaker and it dissolves by disappearing the solution, we have experienced a physical change. This is a dissolution reaction. If we heat the solution and water given off, we can recover back the dissolved solid object.
