2. 273 k
4. Solid CO2
5. vapour into liquid
6. Surface only
11.Both a and b
15. Latent heat of fusion
16. The question is wrong , there will be change of liquid to gas , so the answer is option d.
18. Melting point
19. None of these
20. option (c)
24. Both a and b
26. option a
27. option b
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.
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.
a. when the substance is a solid.