Question

An element 'X' has atomic mass number 85 and number of electrons 17 with atomic number, electronic configation of X also write group number, period and valency.​

Answer 1

Answer:

X is Chlorine

Explanation:

2,8,7,electronic configuration

period is 3

valency 1

group number is 17

Answer 2

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If the atomic number is 17, there must be 17 protons and 17 electrons. Starting from the lowest level, we add electrons to each higher level until we have reached 17 electrons. The electron configuration becomes 1s22s22p63s23p5