I have a question from school:

Assuming that the element Ca had not been discovered, predict using the properties of the known element surrounding Ca its own properties such as its atomic weight and density.

How do I go about this? I don't know how to predict this, it all looks like building blocks in my head. I can't connect the dots yet, please help me solve this. I have done some google searching but to no avail.

What I tried: I understand that

  • atomic mass increase across the period;
  • density increase across the period;
  • density decreases down the group;
  • atomic mass increases down the group.
  • 4
    $\begingroup$ Why not to average the values across the period and group like Mendeleev did?:) $\endgroup$ – andselisk Aug 6 at 13:06
  • $\begingroup$ So, Like I tried that, but I didn't arrive at the same exact value, but very close. I averaged the value of Potassium and Scandium to predict Calcium. $\endgroup$ – Precious Adeyinka Aug 6 at 13:54
  • 2
    $\begingroup$ I think this is what you were supposed to do. Don't expect the exact values. $\endgroup$ – andselisk Aug 6 at 13:59
  • 2
    $\begingroup$ And don't take the density bullets as rules - the various crystal structures play an important role as well. Atomic mass increasing going down is correct. Atomic mass increasing across the period is not always true. $\endgroup$ – Jon Custer Aug 6 at 14:05
  • $\begingroup$ Alright thank you all for your Contributions, I really appreciate @JonCuster. $\endgroup$ – Precious Adeyinka Aug 7 at 8:29