Answer:
Helium is in group 18 of the periodic table. How is helium different from the other elements in this group? = Helium atoms have 2 valence electrons, while atoms of the other elements in the group all have 8 valence electrons.
An emission spectrum will occur when = An electron releases energy and falls back to a lower energy level.
Explanation:
Answer:
It will most likely be the first answer
Explanation:
My Very Excited Mom Just Served Us Nachos
Jupiter Saturn Uranus Neptune
OOH! I know photosynthesis and I have been doing it in school. So the Glucose and oxygen combine to help make the photosynthesis AND it is so important to not forget about Carbon Dioxide and all the features for that because a plant needs carbon dioxide while we need oxygen and plants give out oxygen so that humans can have it and we breathe out carbon dioxide so that plants can have it. We pretty much just help each other out. I plants weren't there than humans wouldn't be there. Hope this helps!
Answer:
Np-237, Ar-40.
Explanation:
Alpha particle is positively charged particle having a mass of 4 unit. Hence,when alpha is removed from any isotope it produces a element having mass 4 units less than original isotope that was before emission. Americium 241 isotopes used in the smoke detector which emit an alpha particle to produce neptunium-237.
Potassium-40 emits positron which is having negative charge to lower one proton and increase one neutron number in the particle and in such way it will produce 
not 
Answer:
1. earth metal 2. halogen 3.The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups. ... Elements in the periodic table are organized according to their properties.
Inventor: Dmitri Mendeleev please name most brainliest
