Which of the following statements about the periodic table is true
1.elements in the same column are similar in their properties
2.elements in the same row are similar in their properties
3.elements that start with the same letter are similar in their properties
4.elements that have the same atomic mass are similar in their properties

Elements in the same column are similar in their properties

Explanation: The columns on the periodic table are also know as group of the periodic table elements in the same group of the periodic table tends to have similar chemical properties because they all have the same number of valence electrons in their outermost shell. This plays an important roles in their reactivity and properties

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer