Hard question !! Is this math .. if not then oh okay cause I’m bad at math but good at everything else so let me think about it !
Answer:
calcium ca
Explanation:
We can see here that the only element that is on the same group (column) as Ba (Barium) is Calcium (Ca).
Answer:
The seven SI base units, which are comprised of:
Length - meter (m)
Time - second (s)
Amount of substance - mole (mole)
Electric current - ampere (A)
Temperature - kelvin (K)
Luminous intensity - candela (cd)
Mass - kilogram (kg)
Explanation:
<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>
