Researchers use a particle detector to follow a decay chain. The nucleus at the start has mass number 190 and atomic number 76.

The detector identifies the emissions in this order:

Four possible records are shown. Each pair gives the mass number and atomic number of the daughter nucleus immediately after an emission.

Record	After beta-minus	After neutron	After alpha
W	$190, 75$	$189, 75$	$185, 73$
X	$190, 77$	$189, 76$	$185, 74$
Y	$189, 76$	$188, 76$	$184, 74$
Z	$190, 77$	$189, 77$	$185, 75$

Which record gives the sequence that should be entered in the research database?

6 Radioactivity

6 Radioactivity Questions