When a metal is heated in a flame, the flame has a distinctive color. this information was eventually extended to the study of stars because a red shift in star color indicates stars are moving away. star color indicates the distance from the earth. the line spectra of stars indicate which elements are present. it allows the observer to determine the size of stars.

The study of metals in chemistry is called inorganic metals.

The correct option is C.

Each metal when burns give the color due to the replacement of the electron because the amount of energy is increased due to heat.

According to the question, the rest of the option is wrong because they don't have any link with the hint.

Hence, the correct option is C that is the line spectra of stars indicating which elements are present.

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Explanation:

Each element has a characteristic spectrum, so analyzing the line spectra of stars tell you what elements are present.

A is wrong. The statement is true, but its not the reason why astronomers study stars.

B is wrong. The colour is a function of the star's temperature.

D is wrong. Line spectra give no information on the size of stars.

answer: the rate of diffusion increases with increase in temperature.

increase in temperature, increases the molecular/particles speed (kinetic energy. diffusion means movement of particles through the material.

generally, the heavier the particle the more it interacts with the environment and more the temperature matters. so higher temperature results in higher diffusion.

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.

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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.