Answer:
The electron configuration for calcium is: 1s2 2s2 2p6 3s2 3p6 4s2. Since calcium is in the fourth row and the second column of the s-block on the periodic table of elements, its electron configuration ends in 4s2. Every lower orbital is filled, starting with the 1s orbital.
Explanation:hope this helps
For the second one it is physical
Answer:
A Broad View of Concept Modeling
Establishing Key Relationships
Levels of Concept Modeling
Explanation:
Half-life of a radioactive substance is the time required to reduce the amount of substance to half of its initial amount.
In present case, half-life is material is given as 1000 years and initial amount of material is given as 400 kg
Answer 1) Since, half-life of radio-active substance is 1000 years, therefore after 1st half life, amount of the material will be left to half the initial amount. Hence, amount of substance left after 1000 years = 400/2 = 200 kg.
Answer 2) For 2000 years, radioactive material has crossed 2 times the half life. Therefore , amount of the material will be left to 1/4 the initial amount. Hence, amount of substance left after 2000 years = 400/4 = 100 kg.
Answer 3) For 4000 years, radioactive material has crossed 4 times the half life. Therefore , amount of the material will be left to 1/16 the initial amount. Hence, amount of substance left after 4000 years = 400/16 = 25 kg.
33.11 trillion kilometers is equivalent to 3.5 light years
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