Imagine that you have collected a sample of gas in a balloon. You know that the sample of gas has a volume of 0.65 L and a density of 0.5 g/L. The balloon is at
room temperature (20°C) and the Earth's average atmospheric pressure (1.00
atm). You then place the balloon in a freezer where the temperature is 0°C. What
is the new density of the gas sample in the balloon?

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.  

colorless gas, exhibiting a blue glow when placed in an electric field

b) solid

its a type of rock

the transfer of heat by electromagnetic radiation is called thermal radiation . it is usually carried out by electromagnetic waves in an energy range just below the visible spectrum, which is the infrared range.

so the answer would be radiation.

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