Answer:
Their valence electrons/properties
Explanation:
Elements in the same group of the periodic table have the same amount of valence electrons, which determines how they bond with other elements in other groups. This also determines their properties such as their reactivity. Since Li, Na, and K are in the same group, they must have similar properties and the same amount of electrons in their outermost shell.
Answer:
the modals of arrangement for first periodic table was. increasing atomic mass and grouping together of elements having similar properties
Answer:- 0.134 seconds
Solution:- The speed is given as 
and the circumference is 24900 miles which is same as the distance light have to covered. It asks to calculate the time required to cover this distance by the light.
We need to do unit conversion from miles to meter as the speed is given in meter per second.
1 mile = 1609.34 meter
So, 
= 40072566 meters
Know that, 
It's rearranged to time as, 
Let's plug in the values in it:
= 0.134 seconds
So, the light would take 0.134 seconds to travel the mentioned speed. The answer without the unit is 0.134.
Answer:
The time recorded in the lab notebook is shorter than the true reaction time because the reaction starts the moment the two solutions were mixed
Explanation:
A chemical reaction is "a process that involves rearrangement of the molecular or ionic structure of a substance, as distinct from a change in physical form or a nuclear reaction" (Oxford dictionary).
A chemical reaction begins immediately the reactants are mixed together in a reaction vessel because the particles of the reactants immediately begin to collide with each other. There is no lost time before reactions begins!
This implies that, the time recorded in the lab notebook is shorter than the true reaction time because the reaction starts the moment the two solutions were mixed.
