Answer:
He is looking for maintenance and reliability quality
Explanation:
He is worried that the product will be reliable and able to be maintained regularly when or if broken.
Dangers faced during natural circumstances
Answer: B) The number of electron in its valence shell.
Explanation:
Outermost electrons of the atoms which can participate in the chemical bond formation is known as valence electrons.
Atoms either transfer or share its valence electrons during chemical bond formation. Atoms transfer or share electrons to attain octet or in other words stability.
Generally, 8 electrons are required in their outermost shell or valence shell in order to attain stability. This rule is known as octet rule.
For example, general electronic configuration of sodium belonging to group 1 is 1s2 2s2 2p6 3s1.
No. of valence electrons in Na = 1
by loosing 1 electron, its outer shell electronic configuration become = 1s2 2s2 2p6 (Octet)
Hence, sodium and other group 1 elements are very reactive.
Similarly, halogens (ns2 np5) by gaining 1 electron attain octet (ns2 np6). Hence halogens are also very reactive.
Carbon atom belonging to group 14 has 4 valence electrons (ns2 np2) and share all 4 valence electrons to attain octet and hence reactive.
Nobel gases have octet in their outermost shell (ns2 np6), hence they are most nonreactive element.
Answer:
16.The circulatory system is composed of in nerve cells and spinal cord: TRUE
17.Leucocytes plays vital role in the body's immune system: true
19.Cell body maintains the health of a neuron.: false
20.Brain is the main organ of the respiratory system
true
Explanation:
