elements have equal number of protons and neutrons
the condensed format is when the closest noble gas with the closest electron configuration is given, this closest noble gas atomic number should be lesser than the atoms atomic number
atomic number of Kr is 36
1 electron in 5s subshell and 7 electrons in 4d subshell.
there's a total of 36 + 1 + 7 = 44 electrons
atomic number of the atom is 44
element with atomic number 44 is Ruthenium - Ru
answer is Ru
Answer:
a.) It is a chemical reaction because a new substance was formed and a colour change occurred in the reaction.
b.) Iron- Metallic element
sulpher- Non-Metalic element
Iron Sulphide- Compound
HOPE IT HELPS....
Answer: 2.88×
atoms 
Explanation: First, using stoichiometry, we must convert this from grams to moles, then from moles to atoms.
1. For the first step, we should also look at the periodic table to find the molar mass of the compound, then use that as the denominator.

2. Now that it is converted to moles, we must convert it to atoms by multiplying it by Avogadro's number.

With this information, we know that there are
total atoms in 0.680 grams
.
I hope this helps! Pls give brainliest!! :)
Mass number of an element write in bottom of it!
So, there 80 would be the mass number of ₈₀Br.
Hope this helps!