Answer:
The Answer is D. principle of original horizontally
The kind of radioactive element is useful for dating an object is one with a half-life close to the age of the object.
<h3>What are radioactive elements?</h3>
Radioactive elements are elements that involved in radioactivity and this comprises of atoms or particles in their nuclei whose atomic nuclei are not stable and they emit radiations to maintain stability.
Therefore, The kind of radioactive element is useful for dating an object is one with a half-life close to the age of the object.
Learn more about radioactive elements below.
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Answer:
BF3
Explanation:
For this question, you need to use the number of valence electrons present in each element. Boron is in group 3/13 on the periodic table so you know it has 3 valence electrons while Fluorine is in group 7/17 so it has 7 valence electrons. These elements are both covalent so they will share electrons. All elements in the first three rows want to reach either have 8 valence electrons or zero valence electrons depending on whichever is easier. When B and F interact each Fluorine will only want to take one electron, but Boron wants to get rid of all 3 electrons, so it will bond with 3 Fluorine to get rid of all its valence electrons.
I hope this helps.
Idk how to write the formula I had this same question
Answer:
the brain and the spinal cord are the two main parts.
