The size of the orbital is determined by the nn The size of the orbital is determined by the quantum number, so the size of the orbital as this value increases. Therefore, an electron in a orbital is closer to the nucleus than is an electron in a orbital. quantum number, so the size of the orbital The size of the orbital is determined by the quantum number, so the size of the orbital as this value increases. Therefore, an electron in a orbital is closer to the nucleus than is an electron in a orbital. as this value increases. Therefore, an electron in a The size of the orbital is determined by the quantum number, so the size of the orbital as this value increases. Therefore, an electron in a orbital is closer to the nucleus than is an electron in a orbital. orbital is closer to the nucleus than is an electron in a The size of the orbital is determined by the quantum number, so the size of the orbital as this value increases. Therefore, an electron in a orbital is closer to the nucleus than is an electron in a orbital. orbital.

Explanation:

The size of the orbital is determined by the principal quantum number (n), so the size of the orbital increases as this value increases. Therefore, an electron in a 1 orbital is closer to the nucleus than is an electron in a 2 orbital.

An atomic orbital can be thought  of as the wave function of an electron in an atom. The Principal Quantum Number (n)  is one of the quantum numbers that are required to describe the distribution of electrons in atoms. This quantum number has positive integral values such as 1, 2, 3 and so on. It also relates to the mean distance of the electron from the nucleus in a given orbital. The larger the quantum number, the greater the mean distance of an electron in that orbital from the nucleus, therefore the orbital will be larger.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.