Ion-icon size should be 100% width and it should touch footer head and bottom in all mobile devices

Ionic Framework ionic-v3
1 
<ion-grid no-padding style="height:100%;">
  <ion-row style="height:100%;">
    <ion-col style="align-self:center;" no-padding>
      <button ion-button clear style="height:100%;margin-top:0px; margin-bottom:0px;">
        <ion-icon name="name="radio-button-off"" style="font-size:300%;" (click)="capture()" large color="light"></ion-icon>
      </button>
    </ion-col> 
   
  </ion-row>
</ion-grid>