Answer:
lol I hate chemical but let me give some advice
Explanation:
Please go on Khan Academy or look at your notes and I promise you can figure out! Seriously, I am trying to be helpful not like the annoying teacher that says "figure it out"
The half life of the substance is 8 hours , Option D is the correct answer.
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What is Half Life ?
Half-life is the time required by an unstable element to reduce to half of its initial value.
The term is commonly used in nuclear physics.
The formula is

N(t) = quantity of the substance remaining
N ₀ = initial quantity of the substance
t = time elapsed
= half life of the substance
The data given in the question is N ₀ = 800 moles , N(t)= 100 , t= 24 hours

Substituting values in the equation


Therefore half life of the substance is 8 hours , Option D is the correct answer.
To know more about Half Life
brainly.com/question/24710827
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Answer:
The Atomic Number of the atom of an element whose model is given is "8" that is option no. 'C' in the question.
Explanation:
An Atom comprises of 3 basic structures that are Protons, Neutrons and Electrons. The central part is the Nucleus which contains protons and neutrons having positive charge and no charge respectively. The electrons are revolving around the nucleus in electronic shells having the negative charge.
<u><em>ATOMIC NUMBER: </em></u>
Atomic number is the number of protons present inside the nucleus of an atom and it determines the place of that particular atom in the <u>Periodic Table.</u>
In the model, given in the question, the nucleus contains 2 types of balls dark gray colored and light gray colored. The key at the bottom shows the dark gray colored ball as having a positive charge and thus it represents the atomic number for the given atom of element which is <u><em>EIGHT (8).</em></u>
So, the atomic number for the given atom is 8 which is element OXYGEN.
Answer:
May 17
Explanation:
When it refers to 0% light it describe a new moon, from a new moon to a full Moon are 14 days, then if you start a full moon on May 3 and you add 14 days it means that the next new Moon would be on May 17.