Write the atomic symbol for the isotope of bismuth with 125 neutrons.
remember the trends in the periodic table:atomic radii decrease from left to right across a period. atomic radii increase from top to bottom in a group. ionic radii of metal cations are smaller than those of their atoms.
thus, the largest atoms are in the lower left corner of the periodic table.
the diagram below shows that k is closest to the lower left, so it is the largest atom. it is also larger than any of the cations.
pbr₃ is a trigonal pyramidal molecule.
the p-br bonds are polar, with their bond dipoles pointing toward the br atoms (see below).
the x-components of the dipoles cancel, but the y-components reinforce each other.
the partially negative br atoms are attracted to the partially positive n atoms in neighboring molecules.
these dipole-dipole forces are the strongest intermolecular forces in pbr₃.
b) water vapor & carbon dioxide