The simple trick which one can consider in such problem where it is asked for positron emission is :
<span>When the atomic number goes DOWN by one and mass number remains unchanged, then a positron is emitted.
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<span>a. </span>

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Here the atomic number decreases by one.
Similarly, options b and d are eliminated.
Option c is also not the answer.
For c, Count the atomic number on left side and compare it with right side. You will see it is 9 on left and 8 on right. Atomic no. did go down by 1. But the atomic mass is changed as well.
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Hope this answers your question Mariaduong159
Radiometric Dating. It's used to find the dates of ricks and other objects based on what the known decay rate of radioactive isotopes. Different forms of this method can also estimate the age of natural and man-made materials.
Outcome (dependent) variable-drinking energy drinks
Test (independent) variable- more aggressive
Answer:
1s2 2s2 2p2
Explanation:
it has 6 electrons in two energy levels so the sub levels are 1s, 2s and 2p