The answers is ATP it  took me a long time to find it but here you go. hope i helped
        
                    
             
        
        
        
More similar to Cesium
Explanation:
The properties of Rubidium are more similar to those of cesium compared to strontium. 
Elements in the same group on the periodic table have similar chemical properties. 
- Rubidium and Cesium are located in the first group on the periodic table.
 - Other elements in this group are lithium, sodium, potassium and francium
 - Strontium belongs to the second group on the periodic table. 
 - The first group have a ns¹ valence shells electronic configuration. 
 - They are all referred to as alkali metals 
 
Learn more: 
Sodium brainly.com/question/6324347
Periodic table brainly.com/question/1704778
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Different amount of species in an area.
        
             
        
        
        
 A solute dissolves in excess solvent to form a solution:
                             solute + solvent → solution
<h3>What is the Enthalpy and their relation ? </h3>
A thermodynamic system's enthalpy, which is one of its properties, is calculated by adding the system's internal energy to the product of its pressure and volume. It is a state function that is frequently employed in measurements of chemical, biological, and physical systems at constant pressure, which the sizable surrounding environment conveniently provides.
A solution is a uniform mixture of two or more components that can exist in the solid, liquid, or gas phases. The amount of heat that is released or absorbed during the dissolving process is known as the enthalpy change of solution (at constant pressure). 
There are two possible values for this enthalpy of solution ( H solution ) : positive (endothermic) and negative (exothermic). It is most straightforward to visualize a hypothetical three-step process occurring between two substances while trying to grasp the enthalpy of solution. The solute is one substance; let's call it A. The solvent is the second component; let's call it B.
The initial procedure exclusively affects the solute A and calls for disabling all intramolecular forces holding it together. This indicates that the molecules of the solute separate. This process' enthalpy is known as H1. Since breaking interactions requires energy, this is always an endothermic process, hence H1>0.
Their sign will be opposite.
To know more about Enthalpy please click here : brainly.com/question/14047927
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