Label each as an endothermic or exothermic reaction or process. a. liquid freezing b. solid melting c. liquid turning into gas d. gas cooling and condensing on the side of a glass e. 2 chemicals mixed together in a beaker and now the beaker feels warm to the touch

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explanation:

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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.

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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.