I would say G sorry if it’s not right
An element or compound which occurs naturally in the earth is a mineral
Half-life is defined as the amount of time it takes a given quantity to decrease to half of its initial value. The equation to describe the decay is
Nt=N0(1/2)

where N0 is the initial quantity, Nt is the remaining quantity after time t, t1/2 is the half-time. So work out the equation, t1/2 = t (-ln2)/ln(Nt/N0) = 11.5*(-ln2)/ln(12.5/100) = 3.83 days
<span>There are few main factors affecting the atomic radii, the outermost electrons and the protons in the nucleus and also the shielding of the internal electrons. I would speculate that the difference in radii is given by the electron clouds since the electrons difference in these two elements is in the d orbital and both has at least 1 electron in the 4s (this 4s electron is the outermost electron in all the transition metals of this period). The atomic radio will be mostly dependent of these 4s electrons than in the d electrons. Besides that, you can see that increasing the atomic number will increase the number of protons in the nucleus decreasing the ratio of the atoms along a period. The Cu is an exception and will accommodate one of the 4s electrons in the p orbital.
</span><span>Regarding the density you can find the density of Cu = 8.96g/cm3 and vanadium = 6.0g/cm3. This also correlates with the idea that if these two atoms have similar volume and one has more mass (more protons; density is the relationship between m/V), then a bigger mass for a similar volume will result in a bigger density.</span>
What happens when chlorine form an ion is that it gains an electron and has an octet in its outer shell ( answer A)
<u><em> Explanation</em></u>
<u><em> </em></u>Chlorine is is in atomic number 17 in periodic table.
The electron configuration of chlorine is 1S2 2S2 2P6 3S2 3P5 or[Ne]3S2 3p5 or 2.8.7.
chlorine therefore has 7 valence electron therefore it gain 1 electron to form Cl- ( ion)
Cl- has 8 electron in its outer shell ( it obeys octet rule of eight valence in outer shell.