Mendeleev used his arrangement of elements in order of increasing mass and repeated properties to predict the mass and properties of undiscovered elements. true or false

True.

Elements are arranged by Mendeleev according to increasing mass in rows to put the elements with similar properties in the same column. Due to undiscovered elements, he was unable to make the complete table, but he left some gaps to put the new elements after their discoveries. In this way, properties of new elements can be identified by arranging the elements in increasing order of mass and repeated properties.

Therefore, the statement "Mendeleev used his arrangement of elements in order of increasing mass and repeated properties to predict the mass and properties of undiscovered elements" is true.

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements