Answer:
1x 10⁴ m or 1000 meters
Explanation:
1 hectometer = 100 meters
10 hectometers = 10 x 100 meters = 1000m
or in scientific form = 1 x 10⁴
The reactivity of metals increases as you move left in a period and as you move down in a group, so Marie needs to know the period and group of the element inside each box. Boxes that show locations in groups 1 or 2 or in period 8 contain the most reactive elements.
Answer:
C) 4.
Explanation:
Hello!
In this case, since the electron configuration of nickel at its ground-state, considering 28 as its atomic number and the number of electrons it has in one atom, is:

We can see it has four energy levels, 1, 2, 3 and 4, which are related to the following principal quantum number, that describes the energy of an electron in the atom and its most probable distance with respect to the nucleus.
Therefore, nickel has C) 4 different principal quantum numbers.
Best regards!
Electron is negative
Proton is positive
Neutron is just nothing really