When scientist first negan grouping element that had similar chemical properties did they call them families, triads, or clusters
Newland called them triads, in 1864. But I am not certain at the time he knew what he had discovered, although later he argued he should have gotten credit for the law of periodic change.
Meyer called them famlies four years later.
When scientists first began grouping elements with similar chemical properties, they employed different terms. In 1864, John Newlands identified groups of three elements with similar properties, which he called "triads." However, it is unclear if Newlands fully understood the significance of his discovery at the time.
Four years later, in 1868, Julius Lothar Meyer independently observed the periodicity of elements and grouped them based on chemical properties. Meyer referred to these groups as "families."
Therefore, both terms were used to describe the groups of elements with similar chemical properties during this earlier period of elemental classification.