It’s A.
They do make observations and perform experiments.
They make multiple experiments and for the experiments, they record the data collected.
Answer:
indeed it 1s22s22p63523p645230104p5 is bromine
Answer:
The change in energy when a neutral atom in the gaseous state adds an electron to form a negative ion.
Explanation:
That is, it is the energy involved in the reaction
X(g) + e⁻ ⟶ X⁻(g)
For most elements, the electron affinity is negative.
However, there are two major exceptions — the values are positive for the elements of Groups 2 and 18 (note the troughs in the graph below).
I’m just letting you know this is really easy you just calculate the molar mass of each compound and divide the amount of the compound (grams) by the molecular Mass