Answer: Option (1) and (2) are correct.
Explanation:
Elements which contain same number of valence electrons tend to show similar chemical properties. This is because having same number of valence electrons will make the atoms to react in a similar way.
For example, Silicon is a group 14 element. So, it contains only 4 valence electrons. Similarly, germanium and lead are group 14 elements and it has 4 valence electrons.
Therefore, silicon, germanium, and lead will have similar chemical properties.
Whereas phosphorous is a group 15 element, and chlorine is a group 17 element.
Thus, we can conclude that out of the given options germanium and lead elements has physical and chemical properties most similar to silicon (Si).
In determining the empirical formula of a compound, you must convert the mass of each element to moles. Since the given mass for this problem is 0.212 grams of Magnesium and 0.140 grams of Oxygen, just divide the mass by the molar mass of Magnesium (24.305 g/mol) and Oxygen (16 g/mol).You’ll get 0.00872 moles of Magnesium and 0.00875 moles of Oxygen. You then divide the each mole value with the smallest calculated number of moles which is 0.00872. You will get an empirical formula of MgO.
B. contain carbon, hydrogen, and oxygen respectively in a 1:2:1 ratio.
C. are produced by living organisms.
D. dissolve in water.
Organic molecules always contain carbon. They need not always be produced by living organisms and do not necessarily dissolve in water. Moreover, they are not restricted by the composition or ratio of other elements.
The answer to this question pertains to organic molecules. Organic molecules are a type of molecules that always contain carbon. This is represented by option A. This is not restricted by the presence of certain elements or the ratio in which they exist such as hydrogen and oxygen (1:2:1 ratio as mentioned in option B). The notion that organic molecules are produced only by living organisms (option C) is not entirely accurate either. Although they are predominantly found in and produced by living organisms, they can also be synthesized in a laboratory setup. Option D states that organic molecules always dissolve in water, which is not the case, as many organic compounds are
hydrophobic, meaning they repel or fail to mix with water. Therefore, the most accurate statement is A: organic molecules always contain carbon.
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Gold and helium are the example of element.
A material is considered an element if it could not be divided into smaller parts by whatever non-nuclear chemical reaction.
Gold is a kind of element which has atomic number 79 and can be represented by Au.
A soft, golden metal, gold is. Gold was incredibly malleable as well as ductile, along with all other metals. Gold also has a good ability to conduct heat as well as electricity.
To know more about element and gold.
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