In an electrically neutral atom of any element, there are equal numbers of
a) protons and neutrons.
b) electrons and protons.
c) electrons and neutrons.
d) atomic number and atomic mass.

Atank contains 240 liters of fluid in which 10 grams of salt is dissolved. brine containing 1 gram of salt per liter is then pumped into the tank at a rate of 6 l/min; the well-mixed solution is pumped out at the same rate. find the number a(t) of grams of salt in the tank at time t.

Esign techniques and materials that reduce the negative environmental impact of a structure are referred to as

An atom of sodium-23 (atomic number = 11) has a positive charge of +1. give this information, how many electrons does it have? how many proteins and neutrons does this atom have