Which statement is true about sand and baking soda? both are mixtures. both are pure substances. sand is a mixture and baking soda is a pure substance. sand is a pure substance and baking soda is a mixture.

The correct answer is Both are mixtures.

Explanation:

Sand and sodium bicarbonate are mixtures of pure substances. In the sand, we can find substances such as silica, usually in the form of quartz, ground limestone, iron, and others. Sodium bicarbonate is composed of pure substances Carbon and Sodium.

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explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.