Question

garnets are a class of minerals which exist in many colors. theyre often used as gemstones. one type of garnet, grossular, has the formula ca₃al₂(sio₄)₃. orange crystals of grossular garnet. grossular is composed of calcium ions (ca²⁺), aluminum ions (al³⁺), and orthosilicate ions (sio₄⁴⁻) bonded together. for each pair of atoms or ions, identify whether they are covalently or ionically bonded in grossular garnet. pair of atoms/ions type of bond ca²⁺ and sio₄⁴⁻ al³⁺ and sio₄⁴⁻ si and o image credit

Explanation:

Step1: Recall bond - type rules

Ionic bonds form between metals and non - metals or polyatomic ions, and covalent bonds form between non - metals.

Step2: Analyze $Ca^{2 + }$ and $SiO_{4}^{4 - }$

Calcium ($Ca$) is a metal and $SiO_{4}^{4 - }$ is a polyatomic anion. So, the bond between $Ca^{2 + }$ and $SiO_{4}^{4 - }$ is ionic.

Step3: Analyze $Al^{3+}$ and $SiO_{4}^{4 - }$

Aluminum ($Al$) is a metal and $SiO_{4}^{4 - }$ is a polyatomic anion. So, the bond between $Al^{3+}$ and $SiO_{4}^{4 - }$ is ionic.

Step4: Analyze $Si$ and $O$

Silicon ($Si$) and oxygen ($O$) are non - metals. So, the bond between $Si$ and $O$ is covalent.

Answer:

$Ca^{2 + }$ and $SiO_{4}^{4 - }$: Ionic
$Al^{3+}$ and $SiO_{4}^{4 - }$: Ionic
$Si$ and $O$: Covalent