Answer:
Why some elements are radioactive (unstable). When the atoms of an element have extra neutrons or protons it creates extra energy in the nucleus and causes the atom to become unbalanced or unstable. Whether radioactive elements can become stable and if so, how. The unstable nucleus of radioactive atoms emit radiation.
Explanation:
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Answer: Cardiovascular System
Explanation:
This involves your heart, blood, veins, and arteries
Answer:
(a) (i) All the elements of a group have similar chemical properties because they have same no. of valence electrons in their outermost shell. (ii) All the elements of a period have different chemical properties because they have different no. of valence electrons in their atoms.
Answer:
The answer to your question is D.
Explanation:
The latitudes near the equator receives the most direct solar energy.
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