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12345 [234]
3 years ago
8

When Dimitri Mendelev first developed the periodic table, one of the most important features that he introduced was starting a n

ew row at a certain point. What factor was most important to Mendelev in knowing when to end a row (period) and start a new one? A) The reactivity of the elements changed drastically. B) The state of the elements went from solid to liquid. C) The boiling point of the elements decreased dramatically. D) The size of the elements jumped from very large to very small.
Chemistry
2 answers:
sashaice [31]3 years ago
6 0

Answer:

A

Explanation:

Phantasy [73]3 years ago
3 0

At the end of a period we get an inert gas which is  very unreactive compared with the previous element ( a halogen).

The answer is A.

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Carbon is important to the structure of macromolecules because it has a valence of 4. what does this mean?
gogolik [260]
The valence part is referring to the outer most ring of electrons.  Carbon only has four on the 'valence' or outer most ring helping it to form bonds with other things.  I hope this helps!! Good Luck!!! :)

5 0
3 years ago
In chemical compound , covalent bonds form when
faltersainse [42]
Pairs of electrons are shared between two nonmetal atoms

hope this helps (:
6 0
3 years ago
How many nitrogen atoms are in 2.79 mo.of NH3
alexandr1967 [171]
1 mol of any particles has 6.02 * 10 ²³ particles.

If we look at 1 NH3 (1 mol NH3 or 1 molecule NH3), we can see that 1 molecule NH3 has 1 atom of N and 3 atoms of H; also 1 mole of NH3 has 1 mole of N atoms and 3 moles of H atoms.

So, 1 mol of NH3 has 1 mol of N atoms,
 and 2.79 mol NH3 have 2.79 mol of N atoms.

2.79 mol of N atoms* 6.02 * 10 ²³ N atoms/ 1 mol N atoms = 1.68*10²⁴ N-atoms 

 Answer is 1.68*10²⁴ N-atoms. 
5 0
3 years ago
WILL GIVE BRAINLIEST Which effect is one likely result of a forest fire? a. extinction b. adaptation c. speciation d. forced mig
MAVERICK [17]

Answer:

d. forced migration

Explanation:

Certain hazardous occurrences affect living organisms in their natural habitat. One of those occurrences is forest fire. Forest fire or vegetation fire is an uncontrollable break out of fire in a vegetation, affecting the inhabitants of the area.

The occurrence of a forest fire will lead to a forced migration of organisms from their natural habitat. Animals and other mobile organisms will be forced to leave behind their devastating habitat and migrate to a less threatened area in order to survive.

4 0
3 years ago
Read 2 more answers
Classify the following substances as acids or bases.
ella [17]
A=acid
B=it say neither it say it’s alkaline
C=acid
D= it say neither it say it’s alkaline
8 0
2 years ago
Read 2 more answers
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