Answer:
Double=4 and triple=6
Explanation:
This is because double bonds are two pairs of electrons are shared between atoms and triple bonds are three pairs, and one pair of electrons is 2, so 2 x 2=4 and 2 x 3=6.
Answer:
3.49X10⁻¹⁷ J
Explanation:
The energy of an electron is given by the equation:

Where Z is the number of protons of the atom and n is the energy level of the electron. For Be, Z = 4.
When n tends to infinity (1/n²) tends to 0, and at this point, the electron has left the atom, so it has ionized.
The ionization energy then is the energy of the electron that left the atom less the energy of the electron in the energy level:
I.E = - (2.18x10⁻¹⁸)x4²x0 - (-(2.18x10⁻¹⁸)x4²x(1/1²))
I.E = 3.49X10⁻¹⁷ J
The electron configuration of Iron is:
[Ar] 3d⁶4s²
growing only enough crops for food to fed the family
Explanation:
subsistence farming is the practice of growing crops only for own use .. some developing countries are only doing farming for their personal use so they are in the stage of developing ..in a country like nepal we not being able to trade our farming .if we want to export then also we arenot getting the good market ..
A. phase changing. Physical change is any change in matter that involves the substance going from one physical state to another, and phase change is most commonly used to describe transitions between solid, liquid and gaseous states of matter.