What element in period 4 has the lowest ionization energy? noble gas, alkali metal, halogen or alkaline earth metal?

alkali metal

Explanation:

The alkali metals in period 4 will have the lowest ionization energy of the elements in the period.

Across a period ionization energy increases progressively from left to right due to decreasing atomic radii caused by the increasing nuclear charge which is not compensated for by successive electronic shells.

Down a group, it decreases.

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

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water at room temperature is flowing through a pipe with pressure taps located 10 ft apart along one section of the pipe, which are connected to a mercury (s=13.6) manometer.