The element with atomic number 71(lutetium) is paramagnetic
This is because all its electrons is not paired . lutetium has electron configuration of (Xe) 4f^14 5d^1 6S^2
Its 5d sub shell is not paired since the d sub shell can accommodate a total of 10 electrons hence lutetium is paramagnetic
Answer:
Chain reaction
Explanation:
A chain reaction is a reaction that sustains itself. It has the ability to continue for a very long time without adding any more materials to the reaction system. It may be succinctly described as a self propagating reaction.
In a nuclear fission, uranium-235 is bombarded with neutrons to produce unstable uranium-236 which disintegrates to form daughter nuclei and produce more neutrons that bombard more uranium-235 and the reaction continues indefinitely.
When you boil water, you aren't changing the elements. You're just making water vapor. However, when you burn paper, it becomes carbon (mostly). So physical changes will not change the substance, only chemical changes will.
3. 9
20. 60 (1hour)
To get to 60 from 20 we multiply by three. 3 times 3 is 9.
A is true
B is true
C is true
D is true
E is false
