2. stem the mass of an atom of helium is about 4.002 atomic units.
the mass of an atom of beryllium is about 2.25 times the mass of an
atom of helium. what is the approximate mass of a beryllium atom?

The approximate mass of beryllium is 9.0045 u.

Explanation:

Given data:

mass of helium= 4.002 u

mass of beryllium which is 2.25 times of mass of helium= ?

Solution:

we will multiply the mass of helium with 2.25 times,

4.002 u × 2.25 = 9.0045 u

so the mass of beryllium atom would be 9.0045 u.

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.