Answer:
B
Explanation:
the group number is=valence electrons. element 1 is in group 1 element 18 is in group 8. 1<8
Answer: Physical change : tearing of paper, fixing of wtaer
Chemical change: rusting of iron , electrolysis of water, Rancidification
Explanation:
Physical change is a change in which there is no rearrangement of atoms and thus no new substance is formed. There is only change in physical state of the substance.
Example: tearing of paper, fixing of wtaer
Chemical change is a change in which there is rearrangement of atoms and thus new substance is formed. There may or may not be a change in physical state.
Example: rusting of iron , electrolysis of water, Rancidification
C- more than one light year or B-exactly one light year
Sodium hydroxide solution and hydrogen gas are produced from the reaction of water and sodium.
<h2>Reaction of sodium and water</h2>
We observe bubbles coming out of the water when the sodium reacts with the water because of the formation of hydrogen gas which is insoluble in water so it moves into the atmosphere.
<h3>Products of the reaction</h3>
Sodium metal reacts rapidly with water to form sodium hydroxide (NaOH) solution and hydrogen gas (H2). This chemical reaction is exothermic because huge amount of heat is release from the solution so we can conclude that sodium hydroxide solution and hydrogen gas are produced from the reaction of water and sodium.
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