They are blue because of hydrogen helium and methane
1) A negatively charged ion is chloride
2) Moving from left to right, valence electrons increase by one.
3) The period number gives information about how many energy levels it has
4) Fluorine has a charge of 1–
5) Potassium and iodine form an ionic bond
The periodic table is an arrangement of elements into groups and periods based on their periodic properties.
In the periodic table, elements are arranged in groups and periods. There are 18 groups and 8 periods.
Chlorine is in group 17, there have seven outermost electrons hence the chlorine atom needs only one more electron in order to attain a stable octet. This is done by accepting one electron to form the negatively charged chloride ion.
As we move from one period to another, one extra electron is added to the outermost shell of elements. Hence, the valence electrons increases by one.
The period to which an element belongs shows you the number of shells or energy levels in the atom of that element.
Fluorine is in group 17. One electron is needed to achieve a stable octet. When an atom accepts one electron, its charge is 1–.
Bonding based on ionic charges occurs between metals and nonmetals. Potassium is a metal of group 1 and iodine is a non metal of group 17 hence they can bond together based on their ionic charges.
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Answer: The energy absorbed by the reaction from the water is 996 Joules.
Explanation:
Energy absorbed by the reaction or energy lost by the water to the reaction,Q.
Mass of the the reaction ,m = 60 g
Specific heat of water = c = 4.15 J\g ^oC
Change is temperature=

Negative sigh indicates that energy was given by the water to the reaction.
The energy absorbed by the reaction from the water is 996 Joules.
Answer:
The energy of an electron in an isolated atom depends on b. n only.
Explanation:
The quantum number n, known as the principal quantum number represents the relative overall energy of each orbital.
The sets of orbitals with the same n value are often referred to as an electron shell, in an isolated atom all electrons in a subshell have exactly the same level of energy.
The principal quantum number comes from the solution of the Schrödinger wave equation, which describes energy in eigenstates
, and for the case of an hydrogen atom we have:

Thus for each value of n we can describe the orbital and the energy corresponding to each electron on such orbital.