Lawrencium has 10 recognized isotopes. Its most stable is 262Lr, with a half-life of about four hours.
Answer:
Hi. I'll explain
Explanation:
If you round it it will be 251
D is the answer (251)
2,8,8
this is the standard shell pattern..
this ok?
Answer:
I, III, and V
Explanation:
All five options are correct.
However, your instructor is probably expecting the answer I, III, and V.
These three elements are on the left-hand side of the Periodic Table. Thus, they tend to lose electrons and form positive ions most easily.
H is the most reluctant to form a cation. Its first ionization energy is 1100 kJ·mol⁻¹.
However, F and He can lose electrons to form cations.
It takes only 1700 kJ·mol⁻¹ to remove an electron from F. However, F tends to add electrons to get a complete valence shell.
Even He, with a complete valence shell, will give up a valence electron for the expenditure of only 2400 kJ·mol⁻¹.
3. A
4. B
5. A
6. E
7. A
8. C
9. A
10. B
Some of these were guesses but they were educated guesses. Best of luck. If some of them are wrong I am sorry. <span />