The SI unit of time in seconds
Answer:J.J. Thomson, he was using a high-vacuum cathode-ray tube
Explanation:(I Googled it)
Explanation:
use the term electron sheilding, the more electrons between the valence el3ctron and nucleus the easier to lose the valence electron (more sheilding = easier to lose)
Hydrogen atom and chlorine atom makes hydrogen chloride molecules.
It is the lowest point in the substance and possesses chemical elements. Atoms don't exist on their own; instead, they combine to create ions and molecules, which combine to create the substances that we can see, feel, and touch.
One or more atoms joined together by covalent (chemical) connections make up molecules. Atoms can be imagined as circles with a central nucleus (consisting of protons and neutrons) and one or more concentric circles surrounding it that represent the "shells" or "levels" in which the electrons surrounding the atom's nucleus are located as well as markings that distinguish the electron. every level
To know more about molecules visit : brainly.com/question/11405437
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<span>The student is incorrect because helium has 2 valence electrons and it's in group 18 because the first energy level is full. Although helium is placed in Group 18 which generally has 8 valence electrons, it does not have 8 valence electrons as the student suggested. It was grouped together with the noble gases because it exhibits similar properties with them. </span>